Vehicle control device

Abstract

In the vehicle control device (5), a calculation unit (5A) calculates a required torque, and a setting unit (5B) sets a first torque threshold based on a maximum torque of the engine (2) and a second torque threshold based on a minimum torque of the engine (2). A determination unit (5C) compares the required torque with the first torque threshold and the second torque threshold to determine whether or not a connection / disconnection mechanism (20) that connects / disconnects the transmission of power from the first rotating electric machine (3) needs to be connected, and a control unit (5D) synchronizes the rotation speed of the first rotating electric machine (3) and then connects the connection / disconnection mechanism (20), thereby improving drivability.

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle equipped with an engine and two rotating electric machines. [Background technology]

[0002] Conventionally, vehicles equipped with an engine and a rotating electric machine (motor, generator, motor generator) (hybrid vehicles or plug-in hybrid vehicles capable of external charging or external power supply) that can switch between driving modes have been put into practical use. Driving modes include an EV mode in which the vehicle runs solely on the motor using the charged power of the battery, a series mode in which the engine drives a generator to generate electricity and the vehicle runs solely on the motor, and a parallel mode in which the vehicle runs using both the engine and the motor. The driving mode is switched by controlling mechanisms such as a sleeve and a clutch that are interposed in the power transmission path within a transaxle device mounted on the vehicle (see Patent Documents 1 and 2).

[0003] In hybrid vehicles that can output engine power and motor power separately, separate power transmission paths are provided: one from the engine to the drive wheels, and the other from the motor to the drive wheels. In such hybrid vehicles, a mode (parallel mode) in which the engine is the main power source is generally selected when the driving load or vehicle speed increases. In parallel mode, when motor assistance is not required, i.e., when the vehicle can run on engine power alone, the motor rotates along with the drive wheels. If the induced voltage generated by the motor's rotation exceeds the voltage of the drive battery, regenerative braking is applied to the vehicle, which can cause discomfort to the driver.

[0004] Conventionally, to avoid this discomfort, unintended regenerative braking has been prevented during high-speed driving by implementing field-weakening control. However, because implementing field-weakening control consumes power, implementing this control is undesirable from the perspective of improving power consumption. Also known is a transaxle device that includes a disconnecting mechanism (clutch) in the power transmission path from the motor to the output shaft to prevent the motor from rotating when motor assist is not required during parallel mode driving, thereby improving power consumption (see Patent Document 3). In such a transaxle device, the disconnecting mechanism is engaged when motor assist is required, and the motor clutch is disengaged when motor assist is not required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-170877 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-180680 [Patent Document 3] International Publication No. 2017 / 217067 Summary of the Invention [Problem to be solved by the invention]

[0006] In the transaxle device described above, when switching the disconnecting mechanism from a disengaged state to an engaged state, it takes time to match the motor rotation speed with the rotation speed of the output shaft (i.e., to synchronize the rotation speed). Furthermore, even without synchronizing the rotation speed, switching can take time due to reasons other than rotation speed synchronization, such as the structure of the gear clutch. In such cases, a response delay occurs before the disconnecting mechanism switches from a disengaged state to an engaged state, resulting in insufficient motor assist or motor regenerative power, which can lead to sluggish vehicle acceleration and deceleration and compromised drivability.

[0007] Furthermore, even when motor assist or the like is not required, there may be situations in which it is better not to disconnect the disconnection mechanism, for example, in a vehicle state where it is difficult to secure the power required for rotational speed synchronization when reconnecting the disconnection mechanism (changing from a disconnected state to an engaged state). In other words, if the disconnection mechanism is always in a disconnected state when motor assist is not required, there is a possibility that problems such as impaired drivability may occur. Therefore, there is a need to appropriately control the disconnection (disconnection) / engagement (connection) of the disconnection mechanism.

[0008] The present invention has been devised in view of the above-mentioned problems, and one of its objectives is to provide a vehicle control device that can improve drivability. However, in addition to this objective, another objective of the present invention is to achieve operational effects that cannot be obtained by conventional techniques, which are derived from the configurations shown in the below-described embodiments of the invention. [Means for solving the problem]

[0009] The disclosed vehicle control device can be realized as the following disclosed aspects (application examples), which solve at least part of the above-mentioned problems. Each of the aspects from aspect 2 onwards is an aspect that can be selected as an additional option, and each of the aspects from aspect 2 onwards is an aspect that can be omitted. None of the aspects from aspect 2 onwards discloses an aspect or configuration that is essential to the present invention.

[0010] Aspect 1. The disclosed vehicle control device is a vehicle control device that transmits the power of an engine and a first rotating electric machine individually to an output shaft on the drive wheel side through different power transmission paths, and also transmits the power of the engine to a second rotating electric machine, and is equipped with a transaxle device that is provided on the first power transmission path from the first rotating electric machine to the output shaft and includes a disconnection mechanism that connects and disconnects the power transmission of the first rotating electric machine, and is equipped with a calculation unit, a setting unit, a judgment unit, and a control unit.

[0011] The calculation unit calculates a required torque of the vehicle. The setting unit sets a first torque threshold based on a maximum torque of the engine and a second torque threshold based on a minimum torque of the engine. The determination unit compares the required torque with the first torque threshold and the second torque threshold to determine whether or not the disconnection mechanism in an open state needs to be engaged. When the determination unit determines that the disconnection mechanism needs to be engaged, the control unit synchronizes the rotation speed of the first rotating electric machine and then engages the disconnection mechanism.

[0012] Aspect 2. In the above-described aspect 1, it is preferable that the vehicle is equipped with a vehicle speed detection unit that detects vehicle speed, and the transaxle device includes an engine-side disconnection mechanism that is provided on a second power transmission path from the engine to the output shaft and that connects and disconnects the power transmission of the engine. In this case, it is preferable that the setting unit sets a second vehicle speed threshold that is higher than a first vehicle speed threshold at which the engine-side disconnection mechanism is switched between connected and disconnected, taking into account the time required for the disconnection mechanism to be reconnected from an open state when the vehicle decelerates, and that the determination unit determines that the disconnection mechanism needs to be connected regardless of the required torque when the vehicle speed is less than the second vehicle speed threshold, and performs the determination of whether or not connection is necessary when the vehicle speed is equal to or greater than the second vehicle speed threshold.

[0013] Aspect 3. In any aspect including Aspect 1 above, it is preferable that the vehicle is equipped with a battery that is a power source for the first rotating electric machine. In this case, it is preferable that the control unit prohibits the disconnecting mechanism from being disconnected when the power of the battery is less than a predetermined power required for the rotation speed synchronization.

[0014] Aspect 4. In an aspect including the above aspect 2, it is preferable that the transaxle device includes a multi-stage gear provided on the second power transmission path and a selection mechanism that couples one of the multi-stage gears to the power transmission path. In this case, it is preferable that the control unit prohibits the release of the coupled disconnection mechanism when the multi-stage gear selected when the vehicle's driving mode is a parallel mode is a gear for transmitting high torque.

[0015] Aspect 5. In an aspect including Aspect 1 above, it is preferable that the setting unit sets, as the first torque threshold, a first torque threshold range having a predetermined margin above or below at least one of the first torque threshold, and sets, as the second torque threshold, a second torque threshold range by providing a predetermined margin above or below at least one of the second torque threshold. In this case, it is preferable that the determination unit determines that the disconnecting mechanism in the released state needs to be connected when the required torque is equal to or greater than an upper limit of the first torque threshold range or equal to or less than a lower limit of the second torque threshold range, and determines that the disconnecting mechanism in the connected state needs to be disconnected when the required torque is equal to or less than the lower limit of the first torque threshold range or equal to or greater than an upper limit of the second torque threshold range. [Effects of the Invention]

[0016] According to the disclosed vehicle control device, the disconnection (release) / engagement (connection) of the disconnection mechanism can be appropriately controlled, thereby improving drivability. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram illustrating an internal configuration of a vehicle equipped with a control device according to an embodiment; [Figure 2] 2 is a schematic left side view of a powertrain equipped with a transaxle device mounted on the vehicle of FIG. 1. FIG. [Figure 3] FIG. 3 is a skeleton diagram illustrating a power train equipped with the transaxle device of FIG. 2. [Figure 4] 4 is an example of a map referred to by the control device according to the embodiment. [Figure 5] 2 is a flowchart illustrating an example of motor connection / disconnection control performed by the control device of FIG. 1. [Figure 6] 10 is an example of a flowchart illustrating a determination of whether or not the motor clutch needs to be engaged based on a required torque, which is included in a third determination process. DETAILED DESCRIPTION OF THE INVENTION

[0018] A vehicle control device according to an embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and is not intended to exclude various modifications or applications of techniques not explicitly described in the embodiment. The configurations of the present embodiment can be modified in various ways without departing from the spirit of the invention. Furthermore, they can be selected or combined as needed.

[0019] [1. Overall structure] The control device 5 of this embodiment is applied to a vehicle 10 shown in FIG. 1 and controls a transaxle 1 mounted on the vehicle 10. The vehicle 10 is a hybrid vehicle equipped with an engine 2 as a drive source, a motor 3 (electric motor, first rotating electric machine) for traveling, and a generator 4 (electric generator, second rotating electric machine) for generating electricity. The generator 4 is connected to the engine 2 and can operate independently of the operating state of the motor 3. The vehicle 10 is equipped with a battery 6 that is the power source for the motor 3.

[0020] The vehicle 10 is also provided with three driving modes: EV mode, series mode, and parallel mode. These driving modes are alternatively selected by the control device 5 according to the vehicle state, driving state, driver required output, etc., and the engine 2, motor 3, and generator 4 are used according to the mode. The motor 3 may have a power generation function (generator function), and the generator 4 may have an electric driving function (motor function).

[0021] EV mode is a driving mode in which the vehicle 10 is driven only by the motor 3 using the charged power of the drive battery 6, while the engine 2 and generator 4 are stopped. EV mode is selected when the driving load and driving speed are low or when the charge level of the battery 6 is high. Series mode is a driving mode in which the engine 2 drives the generator 4 to generate electricity, and that electricity is used to drive the vehicle 10 by the motor 3. Series mode is selected when the driving load is high or the charge level of the battery 6 is low. Parallel mode is a driving mode in which the vehicle 10 is driven mainly by the engine 2, and the motor 3 assists in driving and braking the vehicle 10 as needed, and is selected when the driving speed is high.

[0022] An engine 2 and a motor 3 are connected in parallel to drive wheels 8 via a transaxle 1, and the power of the engine 2 and the motor 3 is transmitted separately. In addition, a generator 4 and drive wheels 8 are connected in parallel to the engine 2 via the transaxle 1, and the power of the engine 2 is transmitted to the generator 4 as well as to the drive wheels 8.

[0023] The transaxle 1 is a power transmission device that integrates a final drive (final reduction gear) including a differential gear 18 (hereinafter referred to as "diff 18") and a transmission (reduction gear), and incorporates multiple mechanisms that transmit power between a driving source and a driven device. The transaxle 1 of this embodiment is configured to be able to switch between high and low gears (switch between high and low gears), and in parallel mode, the control device 5 selects either a high gear or a low gear depending on the driving conditions, required output, etc.

[0024] The engine 2 is an internal combustion engine (gasoline engine, diesel engine) that uses gasoline or diesel as fuel. The engine 2 is a so-called horizontally mounted engine that is arranged sideways so that the direction of the crankshaft 2a (rotating shaft) coincides with the width direction of the vehicle 10, and is fixed to the right side of the transaxle 1. The crankshaft 2a is arranged parallel to the drive shaft 9 of the driving wheels 8. The operating state of the engine 2 may be controlled by the control device 5, or may be controlled by an engine control device (not shown).

[0025] Both the motor 3 and the generator 4 are motor generators that function as both an electric motor and a generator. The motor 3 is a drive source that exchanges power with the battery 6, and mainly functions as an electric motor to drive the vehicle 10 and as a generator during regeneration. The generator 4 functions as an electric motor (starter) when starting the engine 2, and when the engine 2 is running, it is driven by engine power to generate electricity and supply power to the battery 6. Inverters (not shown) that convert DC current to AC current are provided around (or inside) each of the motor 3 and the generator 4. The rotation speeds of the motor 3 and the generator 4 are controlled by controlling the inverters. The operating states of the motor 3, the generator 4, and each inverter may be controlled by the control device 5, or may be controlled by a motor control device or a generator control device (not shown).

[0026] The vehicle 10 is provided with a vehicle speed sensor 42 that detects the vehicle speed, and a shift position sensor 43 that detects the shift position. The vehicle speed sensor 42 is an example of a vehicle speed detection unit that detects the vehicle speed. The vehicle 10 of this embodiment is also provided with a motor rotation speed sensor 44 that detects the rotation speed of the motor 3, an output shaft rotation speed sensor 45 that detects the rotation speed of the output shaft 12 on the drive wheel 8 side, a voltage sensor 46 that detects the voltage of the battery 6, a current sensor 47 that detects the input / output current of the battery 6, and an accelerator opening sensor 49 that detects the amount of depression of the accelerator pedal (accelerator opening) and the depression speed (accelerator opening speed). Information detected by each of the sensors 42 to 47, 49 is transmitted to the control device 5.

[0027] The control device 5 is an electronic control device configured as, for example, an LSI device or an embedded electronic device that integrates a microprocessor, ROM, RAM, etc., and performs integrated control of various devices mounted on the vehicle 10. The control device 5 of this embodiment selects a driving mode according to the driver's required output, etc., and controls various devices (for example, the engine 2 and the motor 3) according to the selected driving mode, as well as controlling the connection and disconnection states of the connection and disconnection mechanisms 20, 30 in the transaxle 1.

[0028] [2. Transaxle] FIG. 2 is a side view of a powertrain 7 including an engine 2, a motor 3, a generator 4, and a transaxle 1, as seen from the left side. Note that the engine 2 is omitted from this side view. FIG. 3 is a skeleton diagram of the powertrain 7 equipped with the transaxle 1 of this embodiment. As shown in FIGS. 2 and 3, the transaxle 1 is provided with six shafts 11 to 16 arranged parallel to one another. Hereinafter, the rotating shaft connected coaxially with the crankshaft 2a will be referred to as the input shaft 11.

[0029] Similarly, the rotating shafts that are coaxially connected to the drive shaft 9, the rotating shaft 3a of the motor 3, and the rotating shaft 4a of the generator 4 are called the output shaft 12, the motor shaft 13, and the generator shaft 14. Furthermore, the rotating shaft arranged on the power transmission path between the input shaft 11 and the output shaft 12 is called the first countershaft 15, and the rotating shaft arranged on the power transmission path between the motor shaft 13 and the output shaft 12 is called the second countershaft 16.

[0030] Both ends of each of the six shafts 11 to 16 are supported by a casing 1C of the transaxle 1 via bearings (not shown). Openings are formed in the side surfaces of the casing 1C located above the input shaft 11, output shaft 12, motor shaft 13, and generator shaft 14, and the shafts are connected to the crankshaft 2a and the like through these openings.

[0031] Three power transmission paths are formed inside the transaxle 1. Specifically, as shown by the two-dot chain lines in Fig. 2, a power transmission path (hereinafter referred to as "first path 51") from the motor 3 to the output shaft 12 via the motor shaft 13, a power transmission path (hereinafter referred to as "second path 52") from the engine 2 to the output shaft 12 via the input shaft 11, and a power transmission path (hereinafter referred to as "third path 53") from the engine 2 to the generator shaft 14 via the input shaft 11 are formed. Here, the first path 51 and the second path 52 are driving power transmission paths, and the third path 53 is a power generation power transmission path.

[0032] The first path 51 is a path for transmitting power from the motor 3 to the output shaft 12 on the drive wheel 8 side, and is responsible for transmitting the power of the motor 3. The first path 51 is an example of a first power transmission path from the motor 3 to the output shaft 12. A connection / disconnection mechanism 20 for connecting and disconnecting the power transmission is installed midway along the first path 51. The connection / disconnection mechanism 20 is configured, for example, by a sleeve-type clutch, a multi-plate clutch, or a planetary gear mechanism including a clutch and a brake. Hereinafter, this connection / disconnection mechanism 20 will be referred to as the "motor clutch 20."

[0033] The second path 52 is a path for transmitting power from the engine 2 to the output shaft 12 on the drive wheel 8 side, and is responsible for transmitting power when the engine 2 is operating. An engine-side disconnecting mechanism 30 (described later) is installed midway along the second path 52, which connects and disconnects the power transmission and switches between high and low modes. The second path 52 is an example of a second power transmission path from the engine 2 to the output shaft 12. The engine-side disconnecting mechanism 30 is composed of, for example, a sleeve-type clutch, a multi-plate clutch, or a planetary gear mechanism including a clutch and a brake. Hereinafter, this engine-side disconnecting mechanism 30 will be referred to as the "engine clutch 30." The third path 53 is a path for transmitting power from the engine 2 to the generator 4, and is responsible for transmitting power when the engine 2 starts and when the engine 2 generates electricity.

[0034] Next, the configuration of the transaxle 1 of this embodiment will be briefly described using Figure 3. Note that the configuration of the transaxle 1 described here is merely one example. In the following description, a "fixed gear" refers to a gear that is integral with a shaft and cannot rotate relative to the shaft. Additionally, an "idle gear" refers to a gear that is pivotally supported so as to be rotatable relative to the shaft.

[0035] Two fixed gears 11H, 11L are provided on the input shaft 11. The two fixed gears 11H, 11L have different numbers of teeth and are constantly meshed with two idler gears 15H, 15L, each having a different number of teeth, that are provided on the first counter shaft 15. In this embodiment, the fixed gear 11L, which has fewer teeth, meshes with the idler gear 15L, which has a larger number of teeth, to form a low gear, and the other fixed gear 11H, which has more teeth, meshes with the other idler gear 15H, which has a smaller number of teeth, to form a high gear.

[0036] The idling gear 15H has a toothed surface on its left side that meshes with the fixed gear 11H, and a dog gear 15d that is coupled to a contact portion that protrudes from the right side of the toothed surface. The idling gear 15L has a toothed surface on its right side that meshes with the fixed gear 11L, and a dog gear 15e that is coupled to a contact portion that protrudes from the left side of the toothed surface. Dog teeth (not shown) are provided on the tip end (radially outer end) of each of the dog gears 15d, 15e.

[0037] The engine clutch 30 is disposed between the two idling gears 15H, 15L and controls the connection and disconnection of the engine 2's power and switches between a high gear and a low gear. The high gear and low gear of the engine clutch 30 are an example of a multi-stage gear provided on the second path 52 (second power transmission path). The engine clutch 30 of this embodiment includes a hub 31 fixed to the first countershaft 15 and an annular sleeve 32 that is non-rotatable relative to the hub 31 (first countershaft 15) and is slidably connected to the first countershaft 15 in the axial direction. The sleeve 32 moves to both the left and right sides from a neutral position in the drawing when an actuator (not shown) is controlled by the control device 5. Spline teeth (not shown) that engage with the dog teeth of the dog gears 15d, 15e are provided on the radially inner side of the sleeve 32. Engagement of the spline teeth with the dog teeth engages the sleeve 32 with the dog gear 15d or the dog gear 15e.

[0038] When the sleeve 32 is in the neutral position, both of the two idling gears 15H, 15L are in an idling state. In this case, even if the engine 2 is operating, the power of the engine 2 (the rotation of the input shaft 11) is not transmitted to the output shaft 12. In other words, in this case, the power transmission of the engine 2 is interrupted.

[0039] When the sleeve 32 moves to either the left or right from the neutral position and engages with the dog gear 15d, 15e of one of the two idler gears 15H, 15L, the rotation of the input shaft 11 is transmitted to one of the idler gears 15H, 15L. Hereinafter, this state will be referred to as the rotationally coupled state. In the transaxle 1 of this embodiment, the sleeve 32 moves to the right and engages with the dog gear 15e of the idler gear 15L, thereby connecting the idler gear 15L of the low gear to the first countershaft 15. Conversely, when the sleeve 32 moves to the left and engages with the dog gear 15d of the idler gear 15H, the idler gear 15H of the high gear is connected to the first countershaft 15. The engine clutch 30 is an example of an engine-side connection / disconnection mechanism 30 and is also an example of a selection mechanism that connects one of the multi-speed gears (high gear and low gear) to the power transmission path.

[0040] Furthermore, in the transaxle 1 of this embodiment, when the sleeve 32 moves, the generator 4 synchronizes the rotational speed of the input shaft 11 (i.e., the rotational speed of the idler gears 15H, 15L) to match the rotational speed of the drive wheels 8. In other words, when the sleeve 32 is engaged with the dog gears 15d, 15e of either the idler gears 15H, 15L (when selecting a high gear or a low gear, or when switching between a high gear and a low gear), prior to the engagement, the control device 5 controls the inverter on the generator 4 side so that the rotational speed of the input shaft 11 matches the rotational speed of the first counter shaft 15.

[0041] The low-side fixed gear 11L is also constantly meshed with a fixed gear 14a provided on the generator shaft 14. In other words, the input shaft 11 and the generator shaft 14 are connected via the two fixed gears 11L, 14a, allowing power to be transmitted between the engine 2 and the generator 4. In addition, a fixed gear 15a is provided on the first counter shaft 15 adjacent to the right side of the low-side idler gear 15L. This fixed gear 15a is constantly meshed with a ring gear 18a of a differential 18 provided on the output shaft 12.

[0042] Two fixed gears 16a, 16b are provided on the second countershaft 16. The right fixed gear 16a is constantly meshed with an idler gear 13b provided on the motor shaft 13, and the left fixed gear 16b is constantly meshed with a ring gear 18a of the differential 18. The idler gear 13b of the motor shaft 13, together with a clutch 21 interposed on the motor shaft 13, constitutes a motor clutch 20. That is, the motor clutch 20 of this embodiment is interposed on the motor shaft 13, and the position of the clutch 21 in the vehicle width direction and the position of the differential 18 in the vehicle width direction are substantially the same. This prevents the axial dimension of the transaxle 1 (dimension in the vehicle width direction) from increasing.

[0043] The clutch 21 is a multi-plate clutch that controls the connection and disconnection state of the power of the motor 3, and has a first engagement element 22 fixed to the motor shaft 13 and a second engagement element 23 fixed to the idling gear 13b. The first engagement element 22 receives power from the motor 3, and the second engagement element 23 outputs power to the drive wheels 8. These engagement elements 22, 23 are driven in directions to move away from each other (disconnected, released) or towards each other (engaged, connected) depending on the oil pressure of the oil that flows in from an oil passage inlet provided in the motor shaft 13, for example.

[0044] When the clutch 21 is engaged, the power of the motor 3 is transmitted to the drive wheels 8 via the idling gear 13b and the fixed gears 16a, 16b, and the rotation of the drive wheels 8 is transmitted to the motor 3. In other words, when the clutch 21 is engaged, power driving and regenerative braking by the motor 3 are possible. Conversely, when the clutch 21 is disengaged while the vehicle is running on the engine 2 (when the motor 3 is stopped), the idling gear 13b spins freely and the rotation of the drive wheels 8 is not transmitted to the motor 3, so the motor 3 is not rotated together and resistance is reduced. The clutch 21 in this embodiment is hydraulically controlled so that it is engaged when the motor 3 is operating (on state) and disengaged when the motor 3 is stopped (off state).

[0045] Note that a pressure adjusting device made up of a plurality of solenoid valves (on-off solenoid valves, linear solenoid valves, etc.) may be provided on the hydraulic circuit, and the oil pressure fed from a pump (not shown) may be adjusted to an appropriate hydraulic pressure to control the engagement and disengagement of clutch 21. Alternatively, an electronically controlled coupling may be provided instead of the pump and multi-plate clutch 21, and the engagement and disengagement of power transmission may be controlled by control device 5. In other words, motor clutch 20 may have an electronically controlled coupling and idler gear 13b.

[0046] [3. Control configuration] In the transaxle 1 described above, if motor assist or motor regeneration is not required while traveling in parallel mode, the motor clutch 20 interposed on the first path 51 is disengaged (released), and the motor 3 is disconnected from the output shaft 12. Hereinafter, the control when disconnecting or engaging the motor clutch 20 (i.e., control when connecting and disconnecting) will be referred to as "motor connection / disconnection control," and this motor connection / disconnection control will be described in detail. Note that in this embodiment, as described above, the control device 5 selects the traveling mode and controls the operating states of the engine 2, motor 3, etc., but because conventional methods can be used for these selections and controls, a description thereof will be omitted here.

[0047] The control device 5 is provided with a calculation unit 5A, a setting unit 5B, a determination unit 5C, and a control unit 5D as elements for performing motor connection / disconnection control. These elements represent some of the functions of a program executed by the control device 5, and are realized by software. However, some or all of the functions may be realized by hardware (electronic circuits), or may be realized by a combination of software and hardware.

[0048] Calculation unit 5A calculates the required torque. In this embodiment, calculation unit 5A calculates the required torque based on information related to accelerator operation (accelerator opening and accelerator opening speed) detected by accelerator opening sensor 49, and transmits the calculated value to setting unit 5B and determination unit 5C. Note that calculation unit 5A may calculate the required torque taking into account the vehicle speed detected by vehicle speed sensor 42 in addition to the accelerator opening.

[0049] The setting unit 5B sets the first torque threshold based on the maximum torque of the engine 2. The first torque threshold is a threshold used to determine whether the motor clutch 20 is engaged or disengaged, and more specifically, is used to determine whether motor assist is required, so it may be called an assist reference torque. The first torque threshold is set taking into consideration that it is more efficient to use motor assist in addition to the torque of the engine 2 rather than providing the required torque solely with the torque of the engine 2. The first threshold torque is preferably set based on the vehicle speed as well as the maximum torque of the engine 2. For example, at high vehicle speeds where the rotational speed of the engine 2 is high, the engine load increases and efficiency tends to decrease. Therefore, the setting unit 5B may set the first torque threshold to a torque lower than the maximum torque of the engine 2. The setting unit 5B transmits the set value to the determination unit 5C.

[0050] Furthermore, setting unit 5B sets the second torque threshold based on the minimum torque of engine 2. The second torque threshold is also a threshold used to determine whether motor clutch 20 is engaged or disengaged. However, since the second torque threshold is used to determine whether regenerative assistance by motor 3 is required when fuel is cut off to engine 2 and engine braking is operating, it can also be called a fuel cut torque. The second torque threshold is set to a value that obtains deceleration by also using regenerative assistance by motor 3 when the negative required torque (required braking torque) cannot be covered by the torque of engine 2 alone. In other words, setting unit 5B sets the minimum torque of engine 2 as the second torque threshold and transmits the set value to determination unit 5C.

[0051] The maximum torque and minimum torque are variable values ​​that change depending on the state of the engine 2 (for example, engine temperature and oil temperature), air pressure, etc. The maximum torque and minimum torque are constantly calculated by the control device 5. The calculated maximum torque and minimum torque are input to the setting unit 5B. However, this is not limited to this, and for example, an engine control device (not shown) may have a function to calculate at least one of the maximum torque and the minimum torque, and can be implemented with appropriate modifications.

[0052] The setting unit 5B may also create a map that the control device 5 uses when implementing motor connection / disconnection control. Fig. 4 is an example of a map that the control device 5 according to the embodiment refers to. The map illustrated in Fig. 4 defines a graph showing the characteristics of the maximum torque (see symbol P1) of the engine 2 versus vehicle speed, and graphs of a first torque threshold (see symbol P2) and a second torque threshold (see symbol P3), which are possessed by the vehicle 10 according to the embodiment.

[0053] The graph of maximum torque P1 of engine 2 shows the maximum positive torque that can be output by engine 2 of vehicle 10 according to vehicle speed (characteristics of engine 2). The first torque threshold is referenced when the vehicle is in a powered driving state by motor 3 (motor assist state), and the second torque threshold is referenced when the vehicle is in a regenerative braking state by motor 3 (regenerative assist state). Hereinafter, the powered driving state by motor 3 may be simply referred to as a powered state, and the regenerative braking state by motor 3 may be simply referred to as a regenerative state.

[0054] Furthermore, the setting unit 5B of this embodiment sets, as the first torque threshold, a first torque threshold range having a predetermined margin above and / or below the first torque threshold. The first torque threshold range set above the first torque threshold may be referred to as an upper first torque threshold range, and the first torque threshold range set below the first torque threshold may be referred to as a lower first torque threshold range. Furthermore, the upper limit value of the first torque threshold range may be referred to as a first motor clutch re-engagement threshold. Furthermore, the lower limit value of the first torque threshold range may be referred to as a first motor clutch disengagement threshold.

[0055] Furthermore, the setting unit 5B of this embodiment sets, as the second torque threshold, a second torque threshold range having a predetermined margin above and / or below the second torque threshold. The second torque threshold range set above the second torque threshold may be referred to as an upper second torque threshold range, and the second torque threshold range set below the second torque threshold may be referred to as a lower second torque threshold range. Furthermore, the upper limit value of the second torque threshold range may be referred to as a second motor clutch release threshold. Furthermore, the lower limit value of the second torque threshold range may be referred to as a second motor clutch re-engagement threshold.

[0056] In Fig. 4, the graph showing the upper limit (first motor clutch re-engagement threshold) of the first torque threshold range (see symbol R1) is denoted by symbol P4, and the graph showing the lower limit (first motor clutch release threshold) of the first torque threshold range is denoted by symbol P5. Furthermore, the graph showing the upper limit (second motor clutch release threshold) of the second torque threshold range (see symbol R2) is denoted by symbol P6, and the graph showing the lower limit (second motor clutch re-engagement threshold) of the second torque threshold range is denoted by symbol P7. Symbols Ra1, Rb1, Ra2, and Rb2 in Fig. 4 represent the upper first torque threshold range, lower first torque threshold range, upper second torque threshold range, and lower second torque threshold range, respectively.

[0057] Furthermore, the setting unit 5B of this embodiment sets a second vehicle speed threshold as a vehicle speed value higher than the first vehicle speed threshold at which the engine clutch 30 is switched between engagement and disengagement, taking into account the time required for the motor clutch 20, which is in a disengaged state, to be re-engaged when the vehicle 10 decelerates. In FIG. 4 , the first vehicle speed threshold is denoted by symbol V1, and the second vehicle speed threshold is denoted by symbol V2. The first vehicle speed threshold and the second vehicle speed threshold may each be fixed values. Alternatively, the setting unit 5B may set these first vehicle speed threshold and second vehicle speed threshold. However, this is not limited to this, and the first vehicle speed threshold and the second vehicle speed threshold may also be variable values.

[0058] The determination unit 5C determines at least whether or not the motor clutch 20 in the released state needs to be engaged. In addition to determining whether or not engagement is needed, the determination unit 5C of this embodiment also determines whether or not the motor clutch 20 should be prohibited from being released and whether or not it needs to be released. The determination processes performed by the determination unit 5C of this embodiment include the following first determination process, second determination process, third determination process, and fourth determination process. Priorities are set for these four processes, and the determination unit 5C may determine whether or not the motor clutch 20 needs to be disengaged and whether or not it needs to be engaged in the order of, for example, the first determination process, the second determination process, the third determination process, and the fourth determination process.

[0059] <First Determination Process> The first determination process is a process for determining whether a predetermined condition (first control condition) is satisfied, and thereby making a determination to prohibit the release of the motor clutch 20. When it is determined in the first determination process that the first control condition is satisfied, the determination unit 5C transmits a "request to prohibit release" to the control unit 5D, which prohibits the release of the motor clutch 20.

[0060] The first control condition may be, for example, the following two conditions: When at least one of these two conditions is met, the determination unit 5C determines that the first control condition is met. (1-1) The vehicle 10 is traveling at a low speed (for example, less than 10 km / h). (1-2) The power of the battery 6 is less than the predetermined power required to synchronize the rotation speed of the motor 3.

[0061] Furthermore, since only positive values ​​are output for the wheel speed, there is a possibility that the vehicle 10 is moving backward at low vehicle speeds. The motor clutch 20 cannot be engaged while the vehicle 10 is moving backward. Condition (1-1) is a condition set to prevent the motor clutch 20 from being unable to be engaged by prohibiting the motor clutch 20 from being released while the vehicle 10 is moving backward.

[0062] Furthermore, condition (1-2) is a condition set to avoid the difficulty of re-engaging the motor clutch 20 when it is difficult to secure the power required for rotational speed synchronization. Before engaging the motor clutch 20, the control unit 5D synchronizes the rotational speed of the motor 3 with the rotational speed of the drive wheels 8. This rotational speed synchronization of the motor 3 is performed using the power of the battery 6. In other words, if the motor clutch 20 is released when the power of the battery 6 is low, there is a possibility that the motor clutch 20 cannot be re-engaged. Condition (1-2) is a condition set to avoid such a situation. The predetermined power required for rotational speed synchronization may be a preset fixed value or a variable value calculated and set depending on the vehicle state, driving state, surrounding environment, etc. The predetermined power may be the maximum power required for rotational speed synchronization. The power (charging rate) of the battery 6 is continuously calculated by the control device 5, or is continuously calculated by a battery control unit (BMU) (not shown) and transmitted to the control device 5.

[0063] <Second Determination Process> The second determination process is a process for determining whether a predetermined condition (second control condition) is satisfied, and thereby making a determination to prioritize disengagement of the motor clutch 20. When it is determined in the second determination process that the second control condition is satisfied, the determination unit 5C transmits a "request for priority disengagement" that prioritizes disengagement of the motor clutch 20 to the control unit 5D.

[0064] The second control condition may be, for example, the following condition: When the following condition is met, the determination unit 5C determines that the second control condition is satisfied. (2-1) The shift position is in N range. The condition (2-1) is set to prevent a change in deceleration due to the connection and disconnection of the motor clutch 20 during coasting in the N range.

[0065] <Third Determination Process> The third determination process is a process for determining whether a predetermined condition (third control condition) is satisfied, and thereby determining whether to engage the motor clutch 20. When it is determined in the third determination process that the third control condition is satisfied, the determination unit 5C transmits an "engagement request" to engage the motor clutch 20 to the control unit 5D.

[0066] The third control condition may be, for example, the following five conditions: When at least one of these five conditions is met, the determination unit 5C determines that the third control condition is met. (3-1) The driving mode is other than parallel mode. (3-2) There is no request to transition to parallel mode (3-3) Transition to engine drive (3-4) Motor assistance is required (3-5) Regenerative assist is required

[0067] Condition (3-1) is a condition set to prevent a loss of driving force due to the disengagement of motor clutch 20. Condition (3-2) is a condition set to prevent a loss of driving force when the vehicle is subsequently transitioned from parallel mode to series mode. Condition (3-3) is a condition set because motor clutch 20 cannot be disengaged unless motor driving torque is set to 0 Nm. This is based on the fact that immediately after transitioning to parallel mode, the vehicle runs on motor 3, and the motor torque is transitioned to engine torque after a predetermined time, but once the transition to engine torque is complete, the motor torque becomes 0 Nm and remains at 0 Nm unless assist is required.

[0068] Conditions (3-4) and (3-5) are conditions related to whether or not the motor clutch 20 needs to be engaged based on the required torque. Condition (3-4) is a condition that can be met in a powering state. Regarding condition (3-4), the determination unit 5C compares the required torque with a first torque threshold value to determine whether or not the motor clutch 20 needs to be engaged in a disengaged state. For example, when the required torque is greater than the first torque threshold value in a powering state, the determination unit 5C determines that motor assist is required and determines that condition (3-4) is met.

[0069] Furthermore, condition (3-5) is a condition that may be met in a regenerative state. Regarding condition (3-5), determination unit 5C compares the required torque with the second torque threshold value to determine whether or not motor clutch 20 needs to be engaged. For example, when the required torque is smaller than the second torque threshold value in a regenerative state, determination unit 5C determines that regenerative assist is required, and determines that condition (3-5) is met.

[0070] The determination unit 5C may use the map shown in Fig. 4 to determine whether or not the motor clutch 20 needs to be engaged based on the required torque. Specifically, the determination unit 5C applies the required torque calculated by the calculation unit 5A and the vehicle speed (current vehicle speed) detected by the vehicle speed sensor 42 to the map, and compares it with a first torque threshold value and a second torque threshold value, thereby determining whether or not the motor clutch 20 needs to be engaged in an open state. As described above, since the setting unit 5B of this embodiment sets the first torque threshold value range and the second torque threshold value range, the determination unit 5C of this embodiment selects a threshold value to be used for the determination (hereinafter referred to as a "determination threshold value") prior to determining whether or not the motor clutch 20 needs to be engaged.

[0071] For example, when the motor clutch 20 is in a disengaged state during powering, the determination unit 5C selects the upper limit of the first torque threshold range (first motor clutch re-engagement threshold P4) as the determination threshold. Also, when the motor clutch 20 is in an engaged state during powering, the determination unit 5C selects the lower limit of the first torque threshold range (first motor clutch disengagement threshold P5) as the determination threshold.

[0072] Similarly, when the motor clutch 20 is in a disengaged state during regeneration, the determination unit 5C selects the lower limit of the second torque threshold range (second motor clutch re-engagement threshold P7) as the determination threshold. Also, when the motor clutch 20 is in an engaged state during regeneration, the determination unit 5C selects the upper limit of the second torque threshold range (second motor clutch disengagement threshold P6) as the determination threshold.

[0073] The determination unit 5C may plot a current operating point from the required torque and the current vehicle speed on the map shown in Fig. 4, compare this operating point with the determination threshold selected as described above, and determine whether or not engagement of the motor clutch 20 is necessary based on the comparison result. That is, when the motor clutch 20 is in a disengaged state during powering, the determination unit 5C determines that engagement of the disengaged motor clutch 20 is necessary if the operating point is equal to or greater than the determination threshold (first motor clutch re-engagement threshold P4). Furthermore, when the motor clutch 20 is in an engaged state during powering, the determination unit 5C determines that disengagement of the engaged motor clutch 20 is necessary if the operating point is less than the determination threshold (first motor clutch disengagement threshold P5).

[0074] Furthermore, in a regenerative state, when the motor clutch 20 is in a disengaged state, the determination unit 5C determines that the disengaged motor clutch 20 needs to be engaged if the operating point is less than the determination threshold (second motor clutch re-engagement threshold P7). Furthermore, in a regenerative state, when the motor clutch 20 is in an engaged state, the determination unit 5C determines that the engaged motor clutch 20 needs to be disengaged if the operating point is equal to or greater than the determination threshold (second motor clutch disengagement threshold P6).

[0075] As described above, since the setting unit 5B of this embodiment sets the second vehicle speed threshold, the determination unit 5C of this embodiment also determines the vehicle speed alone before determining whether or not the motor clutch 20 needs to be engaged (determination of conditions (3-4) and (3-5)). Specifically, when the vehicle speed is less than the second vehicle speed threshold, the determination unit 5C determines that the motor clutch 20 needs to be engaged regardless of the required torque. In other words, in this case, the determination of conditions (3-4) and (3-5) is not performed. Furthermore, when the vehicle speed is equal to or greater than the second vehicle speed threshold, the determination unit 5C performs the determination of whether or not the motor clutch 20 needs to be engaged based on the required torque described above (determination of conditions (3-4) and (3-5)).

[0076] <Fourth Determination Process> The fourth determination process is a process for determining whether a predetermined condition (fourth control condition) is satisfied, and thereby determining whether to release the motor clutch 20. When the determination unit 5C determines in the fourth determination process that the fourth control condition is satisfied, the determination unit 5C transmits a "release request" to release the motor clutch 20 to the control unit 5D.

[0077] The fourth control condition may be, for example, the following condition: When the following condition is met, the determination unit 5C determines that the fourth control condition is satisfied. (4-1) A low gear for transmitting high torque is not selected in the engine clutch 30, and the vehicle speed is equal to or greater than the second vehicle speed threshold value. Since a gear for transmitting high torque, such as a low gear, is selected when driving force is required, the selection of this gear indicates that high torque is likely to be required and responsiveness to accelerator operation is required. Therefore, by prohibiting the motor clutch 20 from being released when condition (4-1) is met, efficient driving can be achieved while suppressing the response delay that occurs each time the motor clutch 20 is re-engaged.

[0078] The control unit 5D maintains or changes the state of the motor clutch 20 to a disengaged state or an engaged state, depending on the result of the determination by the determination unit 5C as to whether or not the motor clutch 20 needs to be engaged. Specifically, when a "request to prohibit disengagement" is transmitted from the determination unit 5C, the control unit 5D prohibits the disengagement of the motor clutch 20. That is, if the motor clutch 20 is in an engaged state, the control unit 5D maintains that state, and if the motor clutch 20 is in a disengaged state, the control unit 5D immediately changes the state to an engaged state. Furthermore, when a "request to prioritize disengagement" is transmitted from the determination unit 5C, the control unit 5D prioritizes the disengagement of the motor clutch 20. That is, if the motor clutch 20 is in a disengaged state, the control unit 5D maintains that state, and if the motor clutch 20 is in an engaged state, the control unit 5D immediately changes the state to an engaged state.

[0079] Furthermore, when an "engagement request" is transmitted from the determination unit 5C, the control unit 5D engages the motor clutch 20. That is, if the motor clutch 20 is in an engaged state, it maintains that state, and if the motor clutch 20 is in a released state, it immediately changes the state to an engaged state. Furthermore, when a "disengagement request" is transmitted from the determination unit 5C, the control unit 5D disengages the motor clutch 20. That is, if the motor clutch 20 is in a released state, it maintains that state, and if the motor clutch 20 is in an engaged state, it immediately changes the state to a released state.

[0080] When changing the motor clutch 20 from a disengaged state to an engaged state, the control unit 5D synchronizes the rotation speed of the motor 3 with the rotation speed of the output shaft 12, and then determines that the rotation speeds are synchronized when the rotation speed difference falls within a predetermined range, and engages the motor clutch 20. Note that "synchronization" here does not only mean that the rotation speed difference is zero (the rotation speeds are completely the same), but also means that a rotation speed difference that does not cause any problems when engaging is allowed.

[0081] [4. Flowchart] FIG. 5 is an example flowchart for explaining the motor connection / disconnection control described above. This flowchart is executed by the control device 5 at a predetermined calculation cycle when the main power supply of the vehicle 10 is on. Note that the driving mode of the vehicle 10 (EV mode, series mode, parallel mode) is set separately from this flowchart. Also, information required for each determination (e.g., vehicle speed, power of the battery 6, on / off state of the motor clutch operation inhibition switch 48, shift position, etc.) is acquired each time. In the flowchart illustrated in FIG. 5, steps S1 and S2 correspond to the first determination process described above, steps S3 and S4 correspond to the second determination process, steps S5 and S6 correspond to the third determination process, and steps S7 and S8 correspond to the fourth determination process.

[0082] In step S1, the determination unit 5C determines whether the first control condition is satisfied. That is, the determination unit 5C determines whether at least one of the multiple condition items included in the first control condition is established. If the first control condition is satisfied, the process proceeds to step S2, where the determination unit 5C outputs a "request to prohibit release" that prohibits release of the motor clutch 20, and the flow returns. On the other hand, if the first control condition is not satisfied, the process proceeds to step S3.

[0083] In step S3, the determination unit 5C determines whether the second control condition is satisfied. In this embodiment, the determination unit 5C determines whether the condition (2-1) is established. If the second control condition is satisfied, the process proceeds to step S4, where the determination unit 5C outputs a "request for release priority" that prioritizes the release of the motor clutch 20, and the process returns. On the other hand, if the second control condition is not satisfied, the process proceeds to step S5.

[0084] In step S5, the determination unit 5C determines whether the third control condition is satisfied. That is, the determination unit 5C determines whether at least one of the multiple condition items included in the third control condition is established. If the third control condition is satisfied, the process proceeds to step S6, where the determination unit 5C outputs an "engagement request" requesting engagement of the motor clutch 20, and the flow returns. Upon receiving the "engagement request," the control unit 5D engages the motor clutch 20 in response to this request. Note that, among the determination processes in step S5, the process of determining whether or not engagement of the motor clutch 20 is required based on the required torque will be described later using the flowchart shown in FIG. 6. On the other hand, if the third control condition is not satisfied, the process proceeds to step S7.

[0085] In step S7, the judgment unit 5C judges whether the fourth control condition is satisfied. In this embodiment, the judgment unit 5C judges whether the condition (4-1) is established. If the fourth control condition is satisfied, the process proceeds to step S8, in which the judgment unit 5C outputs a "release request" requesting release of the motor clutch 20, and the flow returns. On the other hand, if the fourth control condition is not satisfied, the flow returns. In this case, none of the control conditions are satisfied, and the state of the motor clutch 20 does not change.

[0086] 6 is an example of a flowchart for explaining the determination of whether or not the motor clutch 20 needs to be engaged based on the required torque, which is included in the third determination process. This flowchart corresponds to a sub-flowchart of step S5 in FIG.

[0087] In step S11, the determination unit 5C determines whether the vehicle speed is less than the second vehicle speed threshold. If the vehicle speed is less than the second vehicle speed threshold, the process proceeds to step S12, where the determination unit 5C determines that engagement of the motor clutch 20 is necessary (an "engagement request" is output), and the flow returns. On the other hand, if the vehicle speed is equal to or greater than the second vehicle speed threshold, the process proceeds to step S13.

[0088] In step S13, the determination unit 5C determines whether the vehicle is in a powering state or a regenerative state, and if the vehicle is in a powering state, the process proceeds to step S14, and if the vehicle is in a regenerative state, the process proceeds to step S18. In step S14, the determination unit 5C selects a determination threshold value to be used in determining whether or not the motor clutch 20 needs to be engaged. Specifically, if the motor clutch 20 is in a released state, the determination unit 5C selects the first motor clutch re-engagement threshold value as the determination threshold value, and if the motor clutch 20 is in an engaged state, the determination unit 5C selects the first motor clutch release threshold value as the determination threshold value.

[0089] In the following step S15, the determination unit 5C determines whether the required torque is equal to or greater than a determination threshold (first torque threshold) for the current vehicle speed. The required torque is calculated, for example, periodically, by the calculation unit 5A. If the required torque is equal to or greater than the determination threshold for the current vehicle speed, the process proceeds to step S16, where the determination unit 5C determines that engagement of the motor clutch 20 is necessary. If the required torque is less than the determination threshold for the current vehicle speed, the process proceeds to step S17, where the determination unit 5C determines that disengagement of the motor clutch 20 is necessary. Then, the process returns to the original flow.

[0090] Furthermore, when the process proceeds from step S13 to step S18, the determination unit 5C selects a determination threshold value to be used in determining whether or not to engage the motor clutch 20. Specifically, if the motor clutch 20 is in the disengaged state, the determination unit 5C selects the second motor clutch re-engagement threshold value as the determination threshold value, and if the motor clutch 20 is in the engaged state, the determination unit 5C selects the second motor clutch disengagement threshold value as the determination threshold value.

[0091] In the following step S19, the determination unit 5C determines whether the required torque is less than the determination threshold (second torque threshold) for the current vehicle speed. If the required torque is less than the determination threshold for the current vehicle speed, the process proceeds to step S20, where the determination unit 5C determines that engagement of the motor clutch 20 is necessary. If the required torque is equal to or greater than the determination threshold for the current vehicle speed, the process proceeds to step S21, where the determination unit 5C determines that disengagement of the motor clutch 20 is necessary. Then, the process returns from this flow.

[0092] [5. Actions and Effects] (1) In the above-described transaxle 1, when the motor clutch 20 is in an open state, the judgment unit 5C judges whether or not to engage the motor clutch 20 by comparing the required torque with two torque thresholds (a first torque threshold and a second torque threshold).

[0093] Here, these two torque thresholds are respectively set based on the maximum torque and minimum torque of the engine 2. Therefore, for example, if the driving torque and braking torque required for the vehicle can be provided by the engine 2 alone, the motor clutch 20 is kept disengaged, and if not, the motor clutch 20 is determined to be engaged, thereby making it possible to appropriately respond to the demands of the vehicle and the driver, thereby improving drivability.

[0094] Furthermore, it takes time from when it is determined that engagement of the motor clutch 20 is necessary until the engagement is actually completed (a response delay occurs). In response to this, in the control device 5 described above, the first torque threshold is set based on the maximum torque of the engine 2, and the second torque threshold is set based on the minimum torque of the engine 2, so that the response delay can be taken into account when setting these thresholds. This makes it possible to prevent acceleration and deceleration from becoming sluggish when engagement of the motor clutch 20 is necessary, thereby contributing to improved drivability.

[0095] (2) The transaxle 1 described above is provided with an engine clutch 30, and the setting unit 5B sets a second vehicle speed threshold as a vehicle speed value higher than a first vehicle speed threshold, which is a threshold at which the engine clutch 30 is switched between engagement and disengagement. The second vehicle speed threshold is a value that takes into account the time required for the motor clutch 20, which is in a disengaged state, to be re-engaged when the vehicle 10 decelerates. The control device 5 described above determines that engagement of the motor clutch 20 is necessary when the vehicle speed is less than the second vehicle speed threshold, and determines whether engagement of the motor clutch 20 is necessary when the vehicle speed is equal to or greater than the second vehicle speed threshold. Therefore, the motor clutch 20 can be disengaged while the power of the engine 2 is reliably transmitted to the output shaft 12. This makes it possible to reliably avoid loss of driving force and improve drivability.

[0096] (3) Furthermore, the above-described control device 5 prohibits disengagement of the engaged motor clutch 20 when the power of the battery 6 is less than a predetermined power required for rotation speed synchronization. In this way, the above-described control device 5 checks whether the battery 6 has enough power remaining to re-engage (synchronize rotation speed) the motor clutch 20 before disengaging it, and prohibits disengagement if there is not enough power remaining. This prevents the occurrence of a problem in which the disengaged motor clutch 20 cannot be engaged. Therefore, a decrease in drivability is prevented.

[0097] (4) In the transaxle 1 described above, a multi-stage gear (e.g., a high gear and a low gear) and a selection mechanism are provided on the second path 52. Furthermore, the control unit 5D described above disengages the engaged motor clutch 20 when the vehicle 10's driving mode is in parallel mode and the selected multi-stage gear is a gear for transmitting low torque (e.g., a high gear), and prohibits disengagement of the engaged motor clutch 20 when the selected multi-stage gear is a gear for transmitting high torque (e.g., a low gear). Thus, in the parallel mode, when a gear requiring high torque is selected in the engine clutch 30, the control device 5 prohibits disengagement of the motor clutch 20 because assistance by the motor 3 is likely to be required. This prevents frequent switching between engagement and disengagement of the motor clutch 20 and a decrease in drivability due to delayed response.

[0098] (5) In the control device 5 described above, the setting unit 5B sets, as the first torque threshold, a first torque threshold range with a predetermined margin above or below at least one of the first torque threshold, and sets, as the second torque threshold, a second torque threshold range with a predetermined margin above or below at least one of the second torque threshold. The determination unit 5C then compares the required torque with the upper and lower limits of the first torque threshold range and the upper and lower limits of the second torque threshold range to determine whether or not the motor clutch 20 needs to be engaged or disengaged. Therefore, the control device 5 described above can prevent the motor clutch 20 from being frequently engaged and disengaged, thereby preventing a decrease in drivability.

[0099] [6. Other] Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the present invention.

[0100] In the above-described embodiment, the transaxle 1 is exemplified in which the engine clutch 30 (or a part of the engine clutch 30) that switches between high gear and low gear is mounted on the first countershaft 15, but the location of the engine clutch 30 is not particularly limited, and it may be mounted on the input shaft 11, or it may be mounted across the input shaft 11 and the first countershaft 15. Note that the above-described engine clutch 30 has a function as a connecting / disconnecting mechanism 30 and a high / low switching function (a mechanism for selecting between high gear and low gear), but these functions may also be provided as separate mechanisms. Note that the connecting / disconnecting mechanism 30 on the engine 2 side is not an essential component in this case and may be omitted.

[0101] The configuration of the transaxle 1 is also one example. For example, the relative positions of the engine 2, motor 3, and generator 4 with respect to the transaxle 1 are not limited to those described above. The arrangement of the six shafts 11 to 16 within the transaxle 1 may be set according to these relative positions. The arrangement of the gears provided on each shaft within the transaxle 1 is also one example and is not limited to that described above. Furthermore, although the motor clutch 20 is mounted on the motor shaft 13, the arrangement of the motor clutch 20 is not limited to this, and it may be mounted on the second countershaft 16, or may be mounted across the motor shaft 13 and the second countershaft 16.

[0102] In the above-described embodiment, the determination unit 5C determines whether the motor clutch 20 is engaged or disengaged in the order of the first determination process, the second determination process, the third determination process, and the fourth determination process, but this is not limited to this. For example, the order of the first determination process, the second determination process, the third determination process, and the fourth determination process may be reversed. Furthermore, other determination processes may be added, and some of the determination processes may be omitted.

[0103] Furthermore, in each of the first determination process, the second determination process, the third determination process, and the fourth determination process, processes other than those described above may be performed, some processes may be omitted, and various modifications may be made. Furthermore, the condition items exemplified in each determination process are all examples, and some condition items may be omitted, or other condition items may be added. [Explanation of symbols]

[0104] 2 engines 3. Motor (first rotating electric machine) 4. Generator (second rotating electric machine) 5. Control device 5A calculation section 5B Setting section 5C Judgment section 5D control unit 6 Battery 8 drive wheels 10 vehicles 12 Output shaft 20 Motor clutch (disconnection mechanism) 30 Engine clutch (engine side engagement / disengagement mechanism, selection mechanism) 42 Vehicle speed sensor (vehicle speed detection section) 43 Shift position sensor 51 First path (first power transmission path) 52 Second path (second power transmission path)

Claims

1. A control device for a vehicle including a transaxle device that transmits power from an engine and a first rotating electric machine to an output shaft on a drive wheel side individually through different power transmission paths, and also transmits power from the engine to a second rotating electric machine, and that includes a connecting / disconnecting mechanism that is provided on a first power transmission path from the first rotating electric machine to the output shaft and that connects and disconnects the power transmission of the first rotating electric machine, The vehicle is provided with a vehicle speed detection unit that detects vehicle speed, the transaxle device includes an engine-side disconnecting mechanism that is provided on a second power transmission path from the engine to the output shaft and that connects and disconnects the power transmission of the engine, The control device a calculation unit that calculates a required torque of the vehicle; a setting unit that sets a first torque threshold based on a maximum torque of the engine and a second torque threshold based on a minimum torque of the engine; a determination unit that compares the required torque with the first torque threshold value and the second torque threshold value to determine whether or not the disconnecting mechanism in an open state needs to be connected; a control unit that, when the determination unit determines that the connection and disconnection mechanism needs to be connected, synchronizes the rotation speed of the first rotating electric machine and then connects the connection and disconnection mechanism, the setting unit sets a second vehicle speed threshold value, which is higher than a first vehicle speed threshold value at which the engine-side disconnecting mechanism is switched between connected and disconnected, taking into account a time required for the disconnecting mechanism to be reconnected from an open state when the vehicle is decelerating; The determination unit determines that the connection of the disconnection mechanism is necessary regardless of the required torque when the vehicle speed is less than the second vehicle speed threshold, and performs the determination of whether the connection is necessary when the vehicle speed is equal to or greater than the second vehicle speed threshold. A vehicle control device comprising:

2. (delete)

3. the vehicle is equipped with a battery that is a power source for the first rotating electric machine, The control unit prohibits the disconnection mechanism from being released when the power of the battery is less than a predetermined power required for the rotation speed synchronization.

2. The vehicle control device according to claim 1.

4. the transaxle device includes a multi-stage gear provided on the second power transmission path, and a selection mechanism that couples any one of the multi-stage gears to the power transmission path, The control unit prohibits the disconnection mechanism from being released when the multi-stage gear for which the vehicle's running mode is selected as a parallel mode is a gear for transmitting high torque.

2. The vehicle control device according to claim 1.

5. the setting unit sets, as the first torque threshold, a first torque threshold range having a predetermined margin on at least one of an upper side and a lower side of the first torque threshold, and sets, as the second torque threshold, a second torque threshold range by providing a predetermined margin on at least one of an upper side and a lower side of the second torque threshold; The determination unit determining that the disconnecting mechanism in an open state needs to be connected when the required torque is equal to or greater than an upper limit value of the first torque threshold range or equal to or less than a lower limit value of the second torque threshold range; When the required torque is equal to or less than the lower limit value of the first torque threshold range or equal to or more than the upper limit value of the second torque threshold range, it is determined that the disconnection mechanism in the connected state needs to be disconnected.

5. The vehicle control device according to claim 1, 3 or 4.

Images