Control device

Abstract

A control device (20) has a virtual gear shift control mode in which, while a vehicle (10) is traveling by means of the braking / driving force of a first motor generator (MG1), the rotational speed of an engine (ENG) is controlled to a first rotational speed corresponding to the traveling speed of the vehicle (10) and a plurality of predetermined virtual gear shift lines. In the virtual gear shift control mode, the control device (20) performs predetermined start control if there is an acceleration request to the vehicle (10) in a state in which the rotational speed of the engine (ENG) is equal to or less than a predetermined value, and, in the start control, increases the rotational speed of the engine (ENG) to a target rotational speed before the first rotational speed corresponding to the traveling speed of the vehicle (10) and the virtual gear shift lines reaches a predetermined target rotational speed.

Description

Control device

[0001] The present invention relates to a control device for a moving body.

[0002] In recent years, as specific measures against global climate change, efforts to realize a low-carbon society or a decarbonized society have been actively carried out. In moving bodies such as automobiles, reduction of CO2 emissions and improvement of energy efficiency are required, and research and development on electrification technologies for electrifying their drive sources have been conducted.

[0003] As an example of an electrification technology for automobiles, a hybrid electric vehicle (Hybrid Electrical Vehicle) is known. Hybrid electric vehicles are roughly classified into two types: series type and parallel type. A series-type hybrid electric vehicle generates electricity in a generator by the power of an internal combustion engine, supplies the generated electricity to an electric motor, and runs by the power output from the electric motor. On the other hand, a parallel-type hybrid electric vehicle runs by the power output from at least one of an internal combustion engine and an electric motor.

[0004] Further, there is also a hybrid electric vehicle capable of switching between both the series type and the parallel type. Such a hybrid electric vehicle that can switch between both types switches the power transmission system to either a series configuration or a parallel configuration by connecting (in other words, engaging) or disconnecting (in other words, disengaging) a connection means (for example, a clutch).

[0005] Also, in Patent Document 1 below, in order to give a user (driver) who is accustomed to a vehicle having an engine and a transmission a driving feeling without discomfort during series driving, a technique is disclosed in which the engine speed is controlled so that engine speed fluctuations similar to those of a vehicle having an engine and a transmission occur.

[0006] Japanese Patent Application Laid-Open No. 2010-173389

[0007] However, in conventional technology, there is no consideration of providing a virtual gear shift control mode that uses a predetermined virtual gear shift line to control the motor rotation speed (e.g., engine speed) for each moving speed (e.g., vehicle speed) of a moving object (e.g., vehicle) so that the motor rotation speed corresponds to the current moving speed of the moving object. From the viewpoint of ensuring the amount of power generated by the motor driven by the motor, even if such a virtual gear shift control mode is provided, it is desirable to quickly increase the motor rotation speed in response to acceleration requests from the moving object.

[0008] The present invention provides a control device that can quickly increase the engine rotational speed in response to an acceleration request from a moving object, even when a virtual gear shift control mode is provided.

[0009] The present invention relates to a control device for controlling a mobile body comprising: a prime mover; a first electric motor mechanically connected to the prime mover; and a second electric motor mechanically connected to an output unit that outputs driving force, and capable of driving the output unit based on power generated by the first electric motor or power from a battery charged by the power generated by the first electric motor, wherein the control device has a virtual speed shift control mode that controls the rotational speed of the prime mover to a first rotational speed corresponding to the mobile body's moving speed and a predetermined number of virtual speed shift lines when the mobile body is moving due to the braking force of the second electric motor; in the virtual speed shift control mode, when an acceleration request is made to the mobile body while the rotational speed of the prime mover is below a predetermined value, the control device performs a predetermined starting control; and in the starting control, the control device increases the rotational speed of the prime mover to the target rotational speed before the first rotational speed corresponding to the mobile body's moving speed and the virtual speed shift lines reaches a predetermined target rotational speed.

[0010] According to the present invention, even when a virtual gear shift control mode is provided, a control device is available that can quickly increase the engine rotation speed in response to an acceleration request from a moving object.

[0011] This figure shows the schematic configuration of the vehicle 10 of this embodiment. This figure shows a virtual gear shift line and an example of virtual gear shift control using the virtual gear shift line. This figure shows a specific example of the starting control performed by the control device of this embodiment. This flowchart shows an example of the processing performed by the control device of this embodiment. This figure shows another example of the starting control performed in the first scene.

[0012] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. Not all of the features described in the following embodiments are necessarily essential to the present invention. Furthermore, two or more of the features described in the following embodiments 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.

[0013] [Vehicle] First, a vehicle (vehicle 10, described later) equipped with a control device (control device 20, described later) which is one embodiment of the present invention will be described. The vehicle 10 of this embodiment is an example of a mobile body in the present invention.

[0014] The vehicle 10 shown in Figure 1 is a hybrid electric vehicle. The vehicle 10 consists of an engine (prime mover) ENG, a first motor generator (second motor) MG1, a second motor generator (first motor) MG2, a battery BAT, a clutch CL, a power converter 11, various sensors 12, 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.

[0015] 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 (disconnected), and to the second motor generator MG2 and the drive wheels (output units) DW when the clutch CL is engaged (closed). The second motor generator MG2 and the clutch CL will be described later.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 hybrid 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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).

[0026] 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 (disconnects) 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.

[0027] The various sensors 12 are sensors that acquire various information about the vehicle 10. As shown in Figure 1, the various sensors 12 include, for example, a vehicle speed sensor 12a that detects the driving speed of the vehicle 10 (hereinafter also referred to as "vehicle speed"), an AP sensor 12b that detects the AP opening degree (AP: Accelerator Position) which represents the amount of operation on the accelerator pedal of the vehicle 10, and a battery sensor 12c that detects information about the battery BAT (for example, the output voltage, charge / discharge current, and temperature of the battery BAT). Furthermore, the various sensors 12 also include an NE sensor 12d that detects the rotational speed of the engine ENG, in other words, the number of rotations of the engine ENG per unit time (hereinafter also referred to as "engine speed"). Hereafter, the engine speed detected by the NE sensor 12d, in other words, the actual engine speed in the engine ENG, will also be referred to as "engine speed NE". The detection results from the various sensors 12 are sent to the control device 20 as detection signals.

[0028] 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.

[0029] The control device 20 is configured to communicate with the engine ENG, clutch CL, power converter 11, and various sensors 12. The control device 20 controls the engine ENG (in other words, the engine speed NE), controls the power converter 11 to control the first motor generator MG1 and the second motor generator MG2, and controls the clutch CL, by having the processor 21 execute a program stored in the memory 22. As a result, the control device 20 can control the driving mode of the vehicle 10, as will be described later.

[0030] For example, when the vehicle 10 is in motion, the control device 20 derives a target value for the driving force of the vehicle 10 (in other words, the driving force required for the vehicle 10 to move) based on the vehicle speed detected by the vehicle speed sensor 12a and the AP opening degree detected by the AP sensor 12b. The control device 20 then controls the engine ENG and / or the first motor generator MG1, or controls the driving mode of the vehicle 10, so that the driving force of the vehicle 10 becomes the target driving force. The required driving force derived by the control device 20 increases, for example, as the AP opening degree increases.

[0031] The operator 30 is a device that receives operational input from a user (hereinafter also simply referred to as "user") who is an occupant of the vehicle 10 (e.g., the driver). For example, the operator 30 includes a + paddle 31 that receives an upshift operation (described later), a - paddle 32 that receives a downshift operation (described later), and an on / off switch 33 that receives an operation to turn the virtual gear shift control mode (described later) on (operated) or off (deactivated). The + paddle 31 and - paddle 32 may be configured as so-called paddle shifters mounted on the steering wheel.

[0032] [Vehicle Driving Modes] Here, we will explain the driving modes that vehicle 10 can take. Vehicle 10 can take on the following driving modes: EV driving mode, engine driving mode, and hybrid driving mode. Vehicle 10 will then drive in one of these driving modes. As mentioned above, the control device 20 controls which driving mode vehicle 10 will operate in.

[0033] [EV Driving Mode] The EV driving mode is a driving mode 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.

[0034] 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 operation of the engine ENG. Therefore, in EV driving mode, no power is generated by the second motor generator MG2. In EV driving mode, the control device 20 supplies only the power from the battery BAT to the first motor generator MG1, and outputs power from the first motor generator MG1 corresponding to that power, and uses that power to drive the vehicle 10.

[0035] 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 (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.

[0036] [Hybrid Driving Mode] The hybrid driving mode is a driving mode in which at least the electricity 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 electricity.

[0037] To explain in more detail, in hybrid driving mode, the control device 20 disengages the clutch CL. Also in hybrid 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 hybrid driving mode, power is generated by the second motor generator MG2. Also in hybrid 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.

[0038] The maximum power that the second motor generator MG2 can supply to the first motor generator MG1 is greater than the maximum power that the battery BAT can supply to the first motor generator MG1. Therefore, in hybrid 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.

[0039] In hybrid 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 hybrid 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 even greater driving force.

[0040] [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.

[0041] 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.

[0042] Also, in the engine running mode, the control device 20 may supply the power of the battery BAT to the first motor generator MG1 as necessary. Thereby, in the engine running mode, the vehicle 10 can be made to run using the power output by the first motor generator MG1 by supplying the power of the battery BAT, and a greater driving force can be obtained compared to the case where the vehicle 10 is run only by the power of the engine ENG. Further, thereby, the output of the engine ENG can be suppressed compared to the case where the vehicle 10 is run only by the power of the engine ENG, and the fuel efficiency of the vehicle 10 can be improved.

[0043] [Control Performed by the Control Device of the Present Embodiment] Next, an example of the control performed by the control device 20 will be described.

[0044] [Virtual Shift Control Mode (Virtual Shift Control)] When the vehicle 10 is in the hybrid running mode, the control device 20 can take a virtual shift control mode in which the engine speed is controlled so as to provide the user with a driving feeling similar to that of a conventional vehicle equipped with an engine and an automatic transmission (multi-stage transmission).

[0045] When the control device 20 is in the virtual shift control mode, it performs virtual shift control based on a plurality of virtual shift lines. Here, the virtual shift lines are those that define the engine speed corresponding to each vehicle speed, and are preset by imitating the shift lines or engine speed maps used for the shift control of conventional vehicle automatic transmissions.

[0046] In the example shown in FIG. 2, by simulating the engine speed map used for a conventional 8-speed automatic transmission, a total of 8 virtual shift lines, namely the first speed (shown as 1st), the second speed (shown as 2nd), the third speed (shown as 3rd), the fourth speed (shown as 4th), the fifth speed (shown as 5th), the sixth speed (shown as 6th), the seventh speed (shown as 7th), and the eighth speed (shown as 8th), are set. These 8 virtual shift lines are, for example, mapped and stored in advance in the memory 22 or the like. As an example, in the present embodiment, it is assumed that a virtual shift line map MpS obtained by mapping these 8 virtual shift lines is stored in advance in the memory 22.

[0047] The above eight virtual shift lines have a smaller slope of the straight line on the graph (e.g., map) shown in FIG. 2 as they go from the first-speed (1st) virtual shift line, which is the first-speed virtual shift line, to the eighth-speed (8th) virtual shift line, which is the eighth-speed virtual shift line. Therefore, the first-speed virtual shift line (1st) becomes the virtual shift line on the lowest speed side (i.e., suitable for a low vehicle speed state), and the eighth-speed virtual shift line (8th) becomes the virtual shift line on the highest speed side (i.e., suitable for a high vehicle speed state).

[0048] The control device 20 executes virtual shift control using a plurality (e.g., eight) of virtual shift lines as described above. The virtual shift control is control for operating the engine ENG so that the engine speed (first rotational speed) corresponds to the vehicle speed and the virtual shift line. In this specification, when the vehicle 10 travels by the power (control driving force, i.e., braking force or driving force) output by the motor MOT in the hybrid driving mode as described above, the engine speed when controlling the engine ENG according to the vehicle speed and the plurality of virtual shift lines is defined as the first rotational speed. Also, this first rotational speed is hereinafter also referred to as the "foot shaft speed NM".

[0049] Specifically, the control device 20 selects any one of the plurality of virtual shift lines and controls the engine speed NE (i.e., the actual engine speed) to follow the selected virtual shift line. The selection and change of the virtual shift line in the virtual shift control are performed, for example, based on the user's upshift operation and downshift operation. The upshift operation in this embodiment is the operation of the + paddle 31 included in the operator 30. Also, the downshift operation in this embodiment is the operation of the - paddle 32 included in the operator 30.

[0050] Therefore, when the + paddle 31 is operated while virtual gear shift control is being performed, the control device 20 shifts up to a virtual gear on the higher side than the current virtual gear (for example, one virtual gear above the current virtual gear), and controls the engine speed on the virtual gear line corresponding to the virtual gear after the shift up. On the other hand, when the - paddle 32 is operated while virtual gear shift control is being performed, the control device 20 shifts down to a virtual gear on the lower side than the current virtual gear (for example, one virtual gear below the current virtual gear), and controls the engine speed on the virtual gear line corresponding to the virtual gear after the shift down.

[0051] However, shift-up and shift-down operations are not limited to paddle shift operations such as + paddle 31 and - paddle 32, but may also be performed using tip shift operations with the shift lever, or other button operations, for example.

[0052] Furthermore, the control device 20 may be configured to automatically select and change virtual shift lines in virtual shift control. In this case, for example, the control device 20 can use a shift map (not shown) that defines the boundary lines of virtual shift stages (or gear ratios) corresponding to the vehicle speed and AP opening to select one virtual shift line from among several virtual shift lines. For example, if at least one of the vehicle speed or AP opening crosses the upshift boundary line from 1st gear to 2nd gear (in the direction in which at least one of the vehicle speed or AP opening increases) on the shift map, the control device 20 can automatically switch from the 1st virtual shift line (1st) to the 2nd virtual shift line (2nd). Also, if at least one of the vehicle speed or AP opening crosses the downshift boundary line from 4th gear to 3rd gear (in the direction in which at least one of the vehicle speed or AP opening decreases) on the shift map, the control device 20 can automatically switch from the 4th virtual shift line (4th) to the 3rd virtual shift line (3rd).

[0053] Through this virtual gear shift control, the control device 20 can control the engine speed NE so that it behaves similarly to the engine speed in a vehicle equipped with a conventional engine and automatic transmission (for example, the engine speed gradually increases while repeatedly shifting up as the vehicle speed increases), as shown by the thick solid line NeX in Figure 2. Furthermore, as shown by the engine speed NeX, in the vehicle 10, even if the vehicle speed does not decrease, the engine speed NE temporarily decreases when shifting up the virtual gear in the virtual gear shift control.

[0054] [Starting Control] In hybrid driving mode, if virtual shift control is performed using the virtual shift control described above (i.e., virtual shift line map MpS), in situations where the vehicle speed is relatively low, such as when the vehicle 10 is starting, it may not be possible to achieve an appropriate increase in engine speed NE in accordance with the required driving force, and the amount of power generated by the second motor generator MG2 driven by the engine ENG may be insufficient.

[0055] In other words, in order to provide users with a driving feel similar to that of vehicles equipped with conventional engines and automatic transmissions, the engine speed associated with relatively low vehicle speeds in each virtual gear shift map MpS is relatively low (see Figure 2). Furthermore, each virtual gear shift is designed so that the engine speed gradually increases in conjunction with the increase in vehicle speed (see Figure 2).

[0056] Therefore, if the engine ENG is controlled so that the actual engine speed NE always aligns with the virtual gear shift curve, it may be difficult to quickly increase the engine speed NE when the vehicle speed is relatively low, potentially resulting in insufficient power generation from the second motor generator MG2.

[0057] If the power generated by the second motor generator MG2 is insufficient, and the battery BAT cannot supply enough power to the first motor generator MG1, the first motor generator MG1 may not be able to output the required driving force, which could result in the vehicle 10 not accelerating quickly. Such a situation would lead to a decrease in the marketability of the vehicle 10.

[0058] Therefore, assuming that the control device 20 has a configuration that includes a virtual gear shift control mode that performs virtual gear shift control using the virtual gear shift line described above, the engine speed NE is rapidly increased by performing the starting control described later, even in situations where the vehicle speed is relatively low, such as when the vehicle 10 is starting.

[0059] To explain in more detail, in the virtual gear shift control mode, the control device 20 performs a predetermined starting control when an acceleration request is received from the vehicle 10 while the engine speed NE is below a predetermined value. An example of an acceleration request is pressing the accelerator pedal, but it is not limited to this. For example, an acceleration request is not limited to user operations such as pressing the accelerator pedal, but may also be based on instructions from an ADAS (Advanced Driver-Assistance Systems) ECU that realizes any driving assistance function or autonomous driving function.

[0060] Furthermore, the predetermined value that serves as the execution condition for the start control may be, for example, 0 (zero) or a value greater than 0. An example of a value greater than 0 is a predetermined idling speed (for example, 1000 [rpm]). In other words, in the virtual shift control mode, the control device 20 may perform start control when an acceleration request is made to the vehicle 10 while the engine ENG is stopped or idling.

[0061] For example, the control device 20 may have a first mode in which the engine ENG is stopped, and a second mode in which the engine speed NE is maintained at a predetermined value such as the idling speed. The control device 20 may also perform a start control when an acceleration request is made to the vehicle 10 while in either the first or second mode.

[0062] Then, in starting control, the control device 20 increases the engine speed NE, which is the actual engine speed, to the steady-state target speed TgS before the axle rotation speed NM (i.e., first rotation speed), which corresponds to the vehicle speed and virtual gear shift line, reaches a predetermined steady-state target speed TgS. The steady-state target speed TgS is an example of the target rotation speed in this invention.

[0063] By performing this type of starting control, the control device 20 can quickly increase the engine speed NE in the virtual shift control mode, even when an acceleration request is made to the vehicle 10 while the engine speed NE is below a predetermined value (for example, when the vehicle speed is relatively low, such as during starting), thereby ensuring sufficient power generation for the second motor generator MG2 driven by the engine ENG. Therefore, it becomes possible to supply sufficient power to the first motor generator MG1 that drives the drive wheels DW to respond to the acceleration request (in other words, the requested driving force). Furthermore, by quickly increasing the engine speed NE in response to the acceleration request, it is possible to give the user the impression that the vehicle 10 is accelerating smoothly in response to the acceleration request.

[0064] Furthermore, in starting control, the control device 20 sets a steady-state target rotational speed TgS based on the acceleration request and the state of the vehicle 10. For example, the control device 20 sets the steady-state target rotational speed TgS based on the magnitude of the AP opening (e.g., the amount of accelerator pedal operation) as an acceleration request, the engine speed NE as the state of the vehicle 10, the axle rotational speed NM corresponding to the current vehicle speed, the current virtual gear (or target virtual gear), or the required power generation amount in the vehicle 10. This makes it possible to set an appropriate steady-state target rotational speed TgS that takes into account the acceleration request and the state of the vehicle 10.

[0065] Furthermore, in starting control, the control device 20 sets a target rotational speed TgN, which should be the current target value, based on the current engine rotational speed NE and the steady-state target rotational speed TgS. For example, the control device 20 sets a target rotational speed TgN such that the engine rotational speed NE approaches the steady-state target rotational speed TgS, but does not change (suddenly increase) unnaturally.

[0066] As an example, the control device 20 sets a target rotational speed TgN such that the engine rotational speed NE approaches the steady-state target rotational speed TgS by a predetermined amount per unit time, that is, at a predetermined rate. Then, while updating the target rotational speed TgN at a predetermined period, the control device 20 uses this target rotational speed TgN as a target value and performs feedback control of the engine ENG (i.e., engine rotational speed NE) to bring the engine rotational speed NE closer to the steady-state target rotational speed TgS at the above rate.

[0067] [Specific Example of Start Control] Referring to Figure 3, a specific example of start control performed by the control device 20 will be explained. Figure 3 shows the time-series changes of engine speed NE and axle rotation speed NM in two scenarios: "Scene 1" in which an acceleration request is made when the engine ENG is stopped (i.e., in the first mode) and the vehicle 10 starts moving in response to this acceleration request, and "Scene 2" in which an acceleration request is made when the engine ENG is idling (i.e., in the second mode) and the vehicle 10 starts moving in response to this acceleration request.

[0068] [Starting control performed in the first scene] First, an example of starting control performed in the first scene will be explained. In Figure 3, the solid line NE1 shows the time series change of the engine speed NE in the first scene. Also, the dashed line NM in Figure 3 shows the time series change of the axle rotation speed NM in the first and second scenes. And the dashed line TgN1 in Figure 3 shows the time series change of the target rotation speed TgN in the first scene.

[0069] In the example of the first scenario, time t0 shown in Figure 3 is the time when the vehicle 10 and engine ENG are stopped, and when an acceleration request is made for the vehicle 10. When an acceleration request is made when the engine ENG is stopped (i.e., in the first mode), the control device 20 sets the target rotational speed TgN to a predetermined idling rotational speed IS (where idling rotational speed IS > 0). The control device 20 then starts the engine ENG by cranking it with the second motor generator MG2 (see "α" in Figure 3), and sets the started engine ENG to an idling state (i.e., the second mode) (see "β" in Figure 3). In other words, the control device 20 sets the engine rotational speed NE to the idling rotational speed IS.

[0070] Subsequently, the control device 20 gradually increases the target rotational speed TgN from the idling rotational speed IS towards the steady-state target rotational speed TgS (where steady-state target rotational speed TgS > idling rotational speed IS), thereby bringing the engine rotational speed NE closer to the steady-state target rotational speed TgS (see "γ" in Figure 3). At this time, the control device 20 sets a target rotational speed TgN such that the engine rotational speed NE approaches the steady-state target rotational speed TgS at a predetermined rate, and uses this target rotational speed TgN as a target value to feedback control the engine ENG (i.e., engine rotational speed NE), thereby bringing the engine rotational speed NE closer to the steady-state target rotational speed TgS.

[0071] For example, when the current engine speed NE is less than or equal to the axle rotation speed NM corresponding to the vehicle speed at that time, the control device 20 sets the rate to the first rate Rt1. On the other hand, when the current engine speed NE is not less than or equal to the axle rotation speed NM corresponding to the vehicle speed at that time, in other words, when the current engine speed NE is greater than (higher than) the axle rotation speed NM corresponding to the vehicle speed at that time, the control device 20 sets the rate to the second rate Rt2, which is smaller than the first rate Rt1. The first rate Rt1 and the second rate Rt2 are predetermined by, for example, the manufacturer of the vehicle 10.

[0072] Thus, in starting control, the control device 20 increases the rate of change of engine speed per unit time when the current engine speed NE is less than or equal to the axle rotation speed NM (i.e., the first rotational speed) corresponding to the vehicle speed, compared to when the current engine speed NE is greater than the axle rotation speed NM corresponding to the vehicle speed. As a result, even when the current engine speed NE is less than or equal to the axle rotation speed NM corresponding to the vehicle speed, it becomes possible to increase the engine speed NE more quickly than if the same rate as when the current engine speed NE is greater than the axle rotation speed NM corresponding to the vehicle speed were used. Therefore, even when the current engine speed NE is less than or equal to the axle rotation speed NM corresponding to the vehicle speed, it becomes possible to increase the engine speed NE quickly.

[0073] Furthermore, if an acceleration request is received while the engine ENG is stopped, the control device 20 first puts the engine ENG into an idle state, and then increases the engine speed NE to a steady target speed TgS. In other words, if an acceleration request is received while the control device 20 is in the first mode, it switches to the second mode, and after switching to the second mode, it increases the engine speed NE to a steady target speed TgS. This makes it possible to start the engine ENG and quickly increase the engine speed NE when an acceleration request is received in the first mode, thereby ensuring the amount of power generated by the second motor generator MG2 driven by the engine ENG.

[0074] Furthermore, by ensuring sufficient power generation from the second motor generator MG2, it becomes possible to suppress the consumption of electricity stored in the battery BAT. For example, hybrid electric vehicles like vehicle 10 tend to have smaller battery capacities compared to BEVs (Battery Electric Vehicles), which are electric vehicles without generators, and as a result, the battery's SOC (State of Charge) tends to decrease and be depleted more easily. In this regard, as mentioned above, the control device 20 can suppress the consumption of electricity stored in the battery BAT by quickly increasing the engine speed NE to ensure sufficient power generation from the second motor generator MG2, thereby preventing the decrease and depletion of the battery BAT's SOC.

[0075] Furthermore, as the vehicle speed increases, the control device 20 increases the engine speed NE according to the vehicle speed and virtual gear shift line by setting the target gear speed TgN to the axle rotation speed NM corresponding to the vehicle speed at that time (see "δ" in Figure 3). For example, immediately after the vehicle 10 starts moving, the control device 20 can set the target gear speed TgN using the axle rotation speed NM corresponding to the current vehicle speed in the first virtual gear shift line (1st).

[0076] In this way, after the axle rotation speed NM (first rotation speed) reaches the steady-state target rotation speed TgS (target rotation speed), the control device 20 increases the engine rotation speed NE in accordance with the vehicle speed and virtual gear shift line, thereby setting the engine rotation speed NE to match the vehicle speed. This prevents the user from feeling uncomfortable due to the engine rotation speed NE not matching the vehicle speed.

[0077] [Starting control performed in the second scene] Next, an example of starting control performed in the second scene will be explained. In Figure 3, the solid line NE2 shows the time series change of the engine speed NE in the second scene. Also, the dashed line TgN2 in Figure 3 shows the time series change of the target engine speed TgN in the second scene.

[0078] In the example of the second scenario, time t0 shown in Figure 3 is the time when the vehicle 10 is stopped and the engine ENG is idling, and when there is a request for acceleration to the vehicle 10. When an acceleration request is made when the engine ENG is idling (i.e., in the second mode), the control device 20 gradually increases the target rotational speed TgN from the idling rotational speed IS toward the steady-state target rotational speed TgS, thereby bringing the engine rotational speed NE closer to the steady-state target rotational speed TgS (see "ε" in Figure 3). At this time, the control device 20 sets a target rotational speed TgN such that the engine rotational speed NE approaches the steady-state target rotational speed TgS at a predetermined rate, and uses this target rotational speed TgN as a target value to feedback control the engine ENG (i.e., engine rotational speed NE), thereby bringing the engine rotational speed NE closer to the steady-state target rotational speed TgS.

[0079] For example, in the second scenario shown in Figure 3, the current engine speed NE is greater than the axle rotation speed NM corresponding to the vehicle speed at that time, from the moment the acceleration request is made. Therefore, the control device 20 sets the rate to the second rate Rt2. Consequently, in this case, the control device 20 can bring the engine speed NE closer to the steady-state target rotation speed TgS at the second rate Rt2 from the moment the acceleration request is made.

[0080] Then, similar to the first scenario described above, the control device 20, after the axle rotation speed NM reaches the steady target rotation speed TgS as the vehicle speed increases, sets the target rotation speed TgN to the axle rotation speed NM corresponding to the vehicle speed at that time, thereby increasing the engine speed NE in accordance with the vehicle speed and the virtual gear shift line (see "δ" in Figure 3).

[0081] Incidentally, as mentioned above, in vehicle 10, even if the vehicle speed does not decrease, the engine speed NE temporarily decreases when the virtual gear shift in the virtual gear shift control mode (i.e., virtual gear shift control) shifts up. For this reason, it is possible that the engine speed NE may decrease to below the steady-state target speed TgS due to the shifting of the virtual gear in the virtual gear shift control mode. As mentioned above, it is undesirable for the engine speed NE to remain below the steady-state target speed TgS for an extended period of time from the standpoint of ensuring the amount of power generated by the second motor generator MG2.

[0082] Therefore, the control device 20 may increase the engine speed NE to the steady-state target speed TgS if the engine speed NE falls below the steady-state target speed TgS due to a shift in the virtual gear in the virtual gear shift control mode. For example, if the engine speed NE falls below the steady-state target speed TgS due to a shift in the virtual gear in the virtual gear shift control mode, the control device 20 can increase the engine speed NE to the steady-state target speed TgS by performing the same control as the starting control described above. In other words, in this case, the control device 20 can use the steady-state target speed TgS instead of the axle rotation speed NM corresponding to the current vehicle speed to set a target speed TgN such that the engine speed NE approaches the steady-state target speed TgS at a predetermined rate, and then use this target speed TgN as the target value to perform feedback control of the engine ENG.

[0083] In this way, when the engine speed NE falls below the steady-state target speed TgS due to a shift in the virtual gear in the virtual gear control mode, the control device 20 increases the engine speed NE to the steady-state target speed TgS. This allows the engine speed NE to be quickly increased even if it falls below the steady-state target speed TgS due to a shift in the virtual gear, thereby ensuring the power generation amount of the second motor generator MG2.

[0084] [Example of processing performed by the control device] Referring to Figure 4, an example of processing performed by the control device 20 with respect to the aforementioned starting control will be explained. However, please note that the processing described below is merely an example and is not limited to this.

[0085] As shown in Figure 4, the control device 20 acquires various information about the vehicle 10 (hereinafter also referred to as "vehicle information") based on the detection results of various sensors 12 (step S1). The vehicle information acquired through the processing of step S1 includes, for example, information indicating the current engine speed NE, AP opening, current vehicle speed, and the axle rotation speed NM corresponding to the virtual gear position (or target virtual gear position).

[0086] Next, the control device 20 calculates the NM / NE ratio, which is the ratio of the engine speed NE and the foot shaft speed NM obtained in step S1 (step S2). Here, the NM / NE ratio is obtained by dividing the foot shaft speed NM obtained in step S1 by the engine speed NE obtained in step S1.

[0087] Next, the control device 20 derives a base value TgS' of the steady-state target rotational speed TgS based on the AP opening and virtual gear position (or target virtual gear position) obtained in step S1, and the NM / NE ratio calculated in step S2 (step S3).

[0088] For example, the control device 20 pre-stores a map that defines a base value TgS' for each combination of AP opening, virtual gear position (or target virtual gear position), and NM / NE ratio. In step S3, the control device 20 refers to this map to derive a base value TgS' corresponding to the combination of AP opening, virtual gear position (or target virtual gear position) obtained in step S1, and the NM / NE ratio calculated in step S2.

[0089] In this way, the control device 20 can achieve control such that the engine speed NE and the axle speed NM converge smoothly by varying the base value TgS' of the steady-state target rotational speed TgS (in other words, the steady-state target rotational speed TgS) according to the NM / NE ratio.

[0090] Next, the control device 20 derives a steady-state target rotational speed TgS based on the base value TgS' derived in step S3 (step S4). In step S4, for example, if the base value TgS' derived in step S3 is greater than or equal to the shaft rotational speed NM obtained in step S1, the control device 20 may derive the base value TgS' as the steady-state target rotational speed TgS. Alternatively, if the base value TgS' derived in step S3 is less than the shaft rotational speed NM obtained in step S1, the control device 20 may derive the shaft rotational speed NM as the steady-state target rotational speed TgS instead of the base value TgS'.

[0091] Next, the control device 20 performs rate processing (step S5). In the rate processing of step S5, the control device 20 sets a target rotational speed TgN such that the engine rotational speed NE approaches the steady-state target rotational speed TgS using, for example, the first rate Rt1 (when the current engine rotational speed NE is less than or equal to the axle rotational speed NM corresponding to the vehicle speed at that time) or the second rate Rt2 (when the current engine rotational speed NE is not less than or equal to the axle rotational speed NM corresponding to the vehicle speed at that time).

[0092] Next, the control device 20 controls the engine ENG based on the target rotational speed TgN set by the rate processing in step S5 (step S6). Then, the control device 20 determines whether the axle rotational speed NM corresponding to the current vehicle speed and virtual gear position (or target virtual gear position) has reached the steady-state target rotational speed TgS (step S7).

[0093] If the control device 20 determines that the axle rotation speed NM corresponding to the current vehicle speed and virtual gear stage (or target virtual gear stage) has not reached the steady-state target rotation speed TgS (step S7: NO), the control device 20 returns to the process of step S1. On the other hand, if the control device 20 determines that the axle rotation speed NM corresponding to the current vehicle speed and virtual gear stage (or target virtual gear stage) has reached the steady-state target rotation speed TgS (step S7: YES), the control device 20 terminates the series of processes shown in Figure 4 and thereafter increases the engine rotation speed NE according to the vehicle speed and virtual gear stage.

[0094] [Other Examples of Launch Control Performed in Scene 1] Next, with reference to Figure 5, other examples of launch control performed in Scene 1 described above will be explained. In the following explanation, we will focus on the differences from the example explained using Figure 3, and parts that are the same as those explained using Figure 3 will be denoted with the same reference numerals, and their explanations will be omitted or simplified as appropriate.

[0095] As shown in Figure 5, in the area enclosed by the dashed line TgN1 and the dashed line of the symbol "ζ", the control device 20 may perform launch control such that the target rotational speed TgN follows the foot-shaft rotational speed NM after the target rotational speed TgN and the foot-shaft rotational speed NM are the same (or approximately the same) rotational speeds. In other words, the control device 20 may perform launch control such that the target rotational speed TgN approaches the foot-shaft rotational speed NM as the difference (difference in rotational speed) between the target rotational speed TgN and the foot-shaft rotational speed NM becomes smaller, and the target rotational speed TgN is brought closer to the foot-shaft rotational speed NM. By doing so, it is possible to suppress the occurrence of a situation in the short period immediately after launch in which the engine rotational speed NE (i.e., the actual engine rotational speed) drops instantaneously due to the target rotational speed TgN set based on the foot-shaft rotational speed NM, immediately after a rapid increase in engine rotational speed NE.

[0096] Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to such examples. 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.

[0097] For example, in the embodiments described above, the mobile body in the present invention was described as a vehicle 10 which is a hybrid electric vehicle (e.g., a four-wheeled vehicle), but it is not limited to this. For example, the mobile body in the present invention may be a two-wheeled automobile (a so-called motorcycle).

[0098] Furthermore, the components of the embodiments described above may be combined in any way without departing from the spirit of the invention.

[0099] This specification contains at least the following information. Note that the components, etc., in parentheses indicate the corresponding components in the above embodiments, but are not limited thereto.

[0100] (1) A control device (control device 20) for controlling a mobile body comprising: a prime mover (engine ENG); a first electric motor (second motor generator MG2) mechanically connected to the prime mover; and a second electric motor (first motor generator MG1) mechanically connected to an output unit (drive wheel DW) that outputs driving force, and capable of driving the output unit based on power generated by the first electric motor or power from a battery (battery BAT) charged by the power generated by the first electric motor, wherein the control device has a virtual gear shift control mode that controls the rotational speed of the prime mover (engine rotational speed NE) to a first rotational speed (foot shaft rotational speed NM) corresponding to the moving speed of the mobile body and a predetermined plurality of virtual gear shift lines (first virtual gear shift line (1st) to eighth virtual gear shift line (8th)), A control device that, in the virtual gear shift control mode, when an acceleration request is made to the moving body while the rotational speed of the prime mover is below a predetermined value, performs a predetermined starting control, and in the starting control, increases the rotational speed of the prime mover to the target rotational speed before the first rotational speed, which corresponds to the moving speed of the moving body and the virtual gear shift line, reaches a predetermined target rotational speed (steady-state target rotational speed TgS).

[0101] According to (1), in a virtual gear shift control mode in which the rotational speed of the prime mover is controlled to a first rotational speed corresponding to the moving speed of the moving body and a virtual gear shift line, when an acceleration request is made to the moving body while the rotational speed of the prime mover is below a predetermined value, a starting control is performed, and in this starting control, the rotational speed of the prime mover is increased to the target rotational speed before the first rotational speed corresponding to the moving speed of the moving body and a virtual gear shift line reaches the target rotational speed. As a result, in the virtual gear shift control mode, even when an acceleration request is made to the moving body while the rotational speed of the prime mover is below a predetermined value (for example, when the moving speed of the moving body is relatively low), the rotational speed of the prime mover is rapidly increased, making it possible to secure the amount of power generated by the first motor driven by the prime mover. Therefore, it is possible to supply sufficient power to the second motor that drives the output unit to respond to the acceleration request. Furthermore, by rapidly increasing the rotational speed of the prime mover in response to the acceleration request, it is possible to give the user the impression that the moving body is accelerating smoothly in response to the acceleration request.

[0102] (2) A control device as described in (1), wherein the control device sets the target rotational speed based on the acceleration request and the state of the moving body.

[0103] According to (2), since the target rotational speed is set based on the acceleration request and the state of the moving object, it becomes possible to set an appropriate target rotational speed that takes into account the acceleration request and the state of the moving object.

[0104] (3) A control device according to (1) or (2), wherein the control device increases the rotational speed of the prime mover in accordance with the moving speed of the moving body and the virtual gear shift line after the first rotational speed, which is determined by the moving speed of the moving body and the virtual gear shift line, has reached the target rotational speed.

[0105] According to (3), after the first rotational speed, which corresponds to the moving speed of the moving object and the virtual gear shift line, reaches the target rotational speed, the rotational speed of the prime mover is increased according to the moving speed of the moving object and the virtual gear shift line, so that the rotational speed of the prime mover can be matched to the moving speed of the moving object. This prevents the user from feeling uncomfortable due to the rotational speed of the prime mover not matching the moving speed of the moving object.

[0106] (4) A control device according to (1) or (2), wherein, in the starting control, when the rotational speed of the prime mover is less than or equal to the first rotational speed, the control device increases the amount of change per unit time of the rotational speed of the prime mover (first rate Rt1) compared to when the rotational speed of the prime mover is greater than the first rotational speed.

[0107] According to (4), in starting control, when the rotational speed of the prime mover is less than or equal to the first rotational speed, the rate of change of the prime mover's rotational speed per unit time is increased compared to when the rotational speed of the prime mover is greater than the first rotational speed, making it possible to rapidly increase the rotational speed of the prime mover.

[0108] (5) A control device according to (1) or (2), wherein the control device has a first mode for stopping the prime mover and a second mode for maintaining the rotational speed of the prime mover at a predetermined value, and when an acceleration request is made while in the first mode, it switches to the second mode and increases the rotational speed of the prime mover to the target rotational speed after switching to the second mode.

[0109] According to (5), if an acceleration request is made in the first mode, in which the prime mover is stopped, the system switches to the second mode, and after switching to the second mode, the rotational speed of the prime mover is increased to the target rotational speed. This makes it possible to quickly increase the rotational speed of the prime mover even if an acceleration request is made in the first mode.

[0110] (6) A control device according to (1) or (2), wherein the control device increases the rotational speed of the prime mover to the target rotational speed when the rotational speed of the prime mover falls below the target rotational speed due to a gear change in the virtual gear change control mode.

[0111] According to (6), if the rotational speed of the prime mover falls below the target rotational speed due to a gear change in the virtual gear shift control mode, the rotational speed of the prime mover is increased to the target rotational speed. This makes it possible to quickly increase the rotational speed of the prime mover even if the rotational speed of the prime mover falls below the target rotational speed due to a gear change in the virtual gear shift control mode.

[0112] (7) A control device according to (1) or (2), wherein the control device sets a current target value (target rotational speed TgN) based on the rotational speed of the prime mover and the target rotational speed in the starting control, controls the prime mover based on the target value, and after the target value and the first rotational speed become the same rotational speed, causes the target value to follow the first rotational speed.

[0113] According to (7), it is possible to suppress the occurrence of a situation in the short period immediately after starting, where the rotational speed of the prime mover suddenly drops off instantaneously due to the control of the prime mover's rotational speed based on the first rotational speed immediately after a rapid increase in the prime mover's rotational speed.

[0114] 10 Vehicle 20 Control device DW Drive wheels (output unit) ENG Engine (prime mover) MG1 First motor generator (second motor) MG2 Second motor generator (first motor) NE Engine speed (rotational speed of prime mover) TgS Steady-state target speed (target rotational speed) TgN Target speed (target value) NM Foot axle rotation speed (first rotational speed) Rt1 First rate (amount of change)

Claims

1. A control device for controlling a mobile body comprising: a prime mover; a first electric motor mechanically connected to the prime mover; and a second electric motor mechanically connected to an output unit that outputs driving force, and capable of driving the output unit based on power generated by the first electric motor or power from a battery charged by the power generated by the first electric motor, wherein the control device has a virtual speed control mode that controls the rotational speed of the prime mover to a first rotational speed corresponding to the mobile body's moving speed and a predetermined number of virtual speed lines when the mobile body is moving due to the braking force of the second electric motor; in the virtual speed control mode, when an acceleration request is made to the mobile body while the rotational speed of the prime mover is below a predetermined value, a predetermined starting control is performed; and in the starting control, the control device increases the rotational speed of the prime mover to the target rotational speed before the first rotational speed corresponding to the mobile body's moving speed and the virtual speed lines reaches a predetermined target rotational speed.

2. A control device according to claim 1, wherein the control device sets the target rotational speed based on the acceleration request and the state of the moving body.

3. A control device according to claim 1 or 2, wherein the control device increases the rotational speed of the prime mover in accordance with the moving speed of the moving body and the virtual gear shift line after the first rotational speed, which is determined by the moving speed of the moving body and the virtual gear shift line, has reached the target rotational speed.

4. A control device according to claim 1 or 2, wherein, in the starting control, when the rotational speed of the prime mover is less than or equal to the first rotational speed, the control device increases the amount of change per unit time of the rotational speed of the prime mover compared to when the rotational speed of the prime mover is greater than the first rotational speed.

5. A control device according to claim 1 or 2, wherein the control device has a first mode for stopping the prime mover and a second mode for maintaining the rotational speed of the prime mover at a predetermined value, and when an acceleration request is made while in the first mode, it switches to the second mode and increases the rotational speed of the prime mover to the target rotational speed after switching to the second mode.

6. A control device according to claim 1 or 2, wherein the control device increases the rotational speed of the prime mover to the target rotational speed when the rotational speed of the prime mover falls below the target rotational speed due to a gear change in the virtual gear change control mode.

7. A control device according to claim 1 or 2, wherein the control device, in the starting control, sets a current target value based on the rotational speed of the prime mover and the target rotational speed, controls the prime mover based on the target value, and after the target value and the first rotational speed become the same rotational speed, causes the control device to follow the target value with respect to the first rotational speed.

Images