Vehicle control device

Abstract

To provide a vehicular control device which makes it possible to lubricate a transmission mechanism using a mechanical oil pump when a vehicle is traveling while being towed in an engine stop state.SOLUTION: Whenever a cumulative time when a vehicle travels while being towed in an engine stop state and in a ground contact state of a drive wheel reaches a predetermined cumulative time, or whenever a cumulative distance when the vehicle travels while being towed reaches a predetermined cumulative distance, electric motor stop control to control an electric motor so as to stop rotation of the electric motor is executed for a predetermined time. As a result, in a differential mechanism, rotation of a second rotary element to which the electric motor is connected is stopped in a state in which a third rotary element connected to the drive wheel is rotated, so that a first rotary element connected to an input rotary member is rotated, thereby causing a mechanical oil pump to be rotationally driven. Thus, a transmission mechanism can be lubricated using the mechanical oil pump when the vehicle is traveling while being towed in the engine stop state.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle equipped with an engine, an electric transmission mechanism, and a mechanical oil pump. [Background technology]

[0002] There is well known a vehicle control device that includes an engine, an input rotary member to which the engine is connected so as to transmit power, a transmission mechanism to which the power of the engine is input via the input rotary member, and a mechanical oil pump that is driven in conjunction with the rotation of the input rotary member to supply oil that lubricates the transmission mechanism. Patent Document 1 discloses, for example, a vehicle lubrication device that supplies oil that lubricates the transmission mechanism by the mechanical oil pump when the engine is running, and that drives an electric oil pump provided on the vehicle to supply oil that lubricates the transmission mechanism when the vehicle is towed with the engine stopped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-257216 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in vehicles that do not have an electric oil pump, the electric oil pump cannot be used to lubricate the transmission mechanism when the vehicle is towed with the engine stopped. Therefore, in vehicles that do not have an electric oil pump, there is a risk that the oil used to lubricate the transmission mechanism will run short if the vehicle is towed for a long period of time or over a long distance.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can lubricate the transmission mechanism using a mechanical oil pump when the vehicle is being towed with the engine stopped. [Means for solving the problem]

[0006] The gist of a first aspect of the present invention is a control device for a vehicle including: (a) an engine; an input rotary member to which the engine is connected so as to be capable of transmitting power; an electric transmission mechanism having a differential mechanism to which power from the engine is input via the input rotary member and an electric motor connected so as to be capable of transmitting power to the differential mechanism, wherein a differential state of the differential mechanism is controlled by controlling an operating state of the electric motor; and a mechanical oil pump that is driven in accordance with rotation of the input rotary member to supply oil for lubricating the differential mechanism, wherein the differential mechanism includes a first rotary element connected so as to be capable of transmitting power to the input rotary member, a second rotary element to which the electric motor is connected so as to be capable of transmitting power, and a third rotary element connected so as to be capable of transmitting power to drive wheels; and (b) The electric motor is a three-phase AC electric motor driven by an inverter having a plurality of switching elements; and (c) An electric motor stop control is executed for a predetermined time, the electric motor being controlled to stop rotation of the electric motor, each time a cumulative time during towed running in which the vehicle is towed with the engine stopped and the drive wheels in contact with the ground reaches a predetermined cumulative time, or each time a cumulative distance during towed running reaches a predetermined cumulative distance. After the motor stop control is executed, the accumulated time and the accumulated distance are reset to zero, and (d) the motor stop control is a three-phase ON control that controls the inverter so that either one of the upper arms or either one of the lower arms of the switching elements is turned ON. The reason is that. [Effects of the Invention]

[0007] According to the first aspect of the present invention, the electric motor stop control is executed for a predetermined time each time the cumulative time during towed traveling with the engine stopped and the drive wheels in contact with the ground reaches a predetermined cumulative time, or each time the cumulative distance during towed traveling reaches a predetermined cumulative distance. After the motor stop control is executed, the accumulated time and accumulated distance are reset to zero.As a result, in the differential mechanism, the rotation of the second rotating element connected to the electric motor is stopped while the third rotating element connected to the drive wheels is rotated, causing the first rotating element connected to the input rotating member to rotate and drive the mechanical oil pump to rotate. Therefore, when the vehicle is being towed with the engine stopped, the mechanical oil pump can be used to lubricate the transmission mechanism. The motor stop control is a three-phase ON control, so that the rotation of the motor is stopped appropriately when the vehicle is being towed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and control systems for various controls in the vehicle. [Figure 2] This is a collinear diagram showing the relative relationship between the rotational speeds of the rotating elements in the transmission section. [Figure 3] FIG. 2 is a diagram illustrating an example of an electrical configuration of an electric circuit unit. [Figure 4] FIG. 10 is a diagram illustrating MG1 three-phase ON control. [Figure 5] 1 is a flowchart illustrating the main control operations of the electronic control device, and is a flowchart illustrating the control operations for lubricating a planetary gear device, etc., using an MOP during flat towing. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] Fig. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and also illustrates essential parts of a control system for various controls in the vehicle 10. In Fig. 1, the vehicle 10 includes an engine 12, a first electric motor MG1, and a second electric motor MG2. The vehicle 10 also includes drive wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14. The vehicle 10 is an electric vehicle, particularly a hybrid vehicle, that includes the engine 12 and the second electric motor MG2 and functions as a power source.

[0011] The engine 12 is a known internal combustion engine. An engine control device 50 provided in the vehicle 10 is controlled by an electronic control device 90 (described later), whereby the engine torque Te of the engine 12 is controlled.

[0012] The first electric motor MG1 and the second electric motor MG2 are each a rotating electric machine, a so-called motor generator. The first electric motor MG1 and the second electric motor MG2 are each connected to a high-voltage battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The inverter 52 of the first electric motor MG1 and the second electric motor MG2 is controlled by an electronic control device 90 (described later), thereby controlling the MG1 torque Tg of the first electric motor MG1 and the MG2 torque Tm of the second electric motor MG2. The first electric motor MG1 and the second electric motor MG2 are provided in a case 18 attached to the vehicle body.

[0013] The power transmission device 16 includes, within a case 18, a damper 20, an input shaft 22, a transmission unit 24, a compound gear 26, a driven gear 28, a driven shaft 30, a final gear 32, a differential gear 34, a reduction gear 36, and the like. The power transmission device 16 also includes, within the case 18, a rotor shaft RSmg1 integrally connected to the rotor MG1r of the first electric motor MG1, and a rotor shaft RSmg2 integrally connected to the rotor MG2r of the second electric motor MG2. The power transmission device 16 also includes, within the case 18, a pair of drive shafts 38 connected to the differential gear 34, and the like.

[0014] The input shaft 22 functions as an input rotating member of the transmission unit 24 and is connected to the crankshaft 12a of the engine 12 via a damper 20 or the like. The input shaft 22 is an input rotating member to which the engine 12 is connected so as to be capable of transmitting power, and receives power from the engine 12. The transmission unit 24 is connected to the input shaft 22. The compound gear 26 is a rotating body on the output side of the transmission unit 24. A drive gear 26a is formed on a portion of the outer circumferential surface of the compound gear 26. The drive gear 26a is an output rotating member of the transmission unit 24. The driven gear 28 meshes with the drive gear 26a. The driven shaft 30 fixedly mounts the driven gear 28 and a final gear 32 so that they cannot rotate relative to each other. The final gear 32 has a smaller diameter than the driven gear 28 and meshes with a differential ring gear 34a of the differential gear 34. The reduction gear 36 has a smaller diameter than the driven gear 28 and is in mesh with the driven gear 28. A rotor shaft RSmg2 is connected to the reduction gear 36, and a second electric motor MG2 is connected thereto so as to be able to transmit power.

[0015] The power transmission device 16 transmits the power output from the engine 12 to the driven gear 28 via the transmission unit 24. The power transmission device 16 also transmits the power output from the second electric motor MG2 to the driven gear 28 via a reduction gear 36. The power transmission device 16 then transmits the power transmitted to the driven gear 28 to the drive wheels 14 sequentially via a driven shaft 30, a final gear 32, a differential gear 34, a drive shaft 38, etc.

[0016] The transmission unit 24 includes a first electric motor MG1, a rotor shaft RSmg1, and a planetary gear set 40. The planetary gear set 40 is a known single-pinion planetary gear set including a sun gear S, a carrier CA, a ring gear R, and a pinion P. The sun gear S is power-transmittably connected to the rotor shaft RSmg1. That is, the sun gear S is power-transmittably connected to the first electric motor MG1. The carrier CA is power-transmittably connected to the input shaft 22. That is, the carrier CA is power-transmittably connected to the engine 12 via the input shaft 22, etc. The ring gear R is formed on a part of the inner circumferential surface of the compound gear 26 and is integrally connected to the drive gear 26a. That is, the ring gear R is power-transmittably connected to the drive wheels 14. The pinion P is supported by the carrier CA so as to be rotatable and revolvable. The ring gear R meshes with the sun gear S via the pinion P.

[0017] The planetary gear set 40 functions as a differential mechanism that generates a differential action. The power of the engine 12 is input to the planetary gear set 40 via the input shaft 22. The first electric motor MG1 is an electric motor that is connected to the planetary gear set 40 so that power can be transmitted. The planetary gear set 40 is a power split mechanism that mechanically splits the power of the engine 12 that is input to the carrier CA between the first electric motor MG1 and the drive gear 26a. The transmission unit 24 is a known electric transmission mechanism in which the differential state of the planetary gear set 40 is controlled by controlling the operating state of the first electric motor MG1.

[0018] The vehicle 10 further includes a mechanical oil pump 56. In this embodiment, the mechanical oil pump 56 is referred to as the MOP 56. The MOP 56 is connected to the input shaft 22 so as to be capable of transmitting power. The MOP 56 is driven to rotate by the engine 12, thereby supplying oil Fld that is used to lubricate and cool various parts of the power transmission device 16. In other words, the MOP 56 is driven in conjunction with the rotation of the input shaft 22, thereby supplying oil Fld that lubricates the planetary gear unit 40 and the like.

[0019] FIG. 2 is a collinear diagram showing the relative relationship between the rotational speeds of the rotating elements in the transmission unit 24. In FIG. 2, three vertical lines Y1, Y2, and Y3 correspond to the three rotating elements of the planetary gear set 40 that constitutes the transmission unit 24. The vertical line Y1 represents the rotational speed of the sun gear S corresponding to the second rotating element RE2 to which the first electric motor MG1 (see "MG1" in the figure) is power-transmittably connected. The vertical line Y2 represents the rotational speed of the carrier CA corresponding to the first rotating element RE1 to which the engine 12 (see "ENG" in the figure) is power-transmittably connected. The MOP 56 (see "MOP" in the figure) is connected to the input shaft 22 to which the engine 12 is power-transmittably connected. The vertical line Y3 represents the rotational speed of the ring gear R corresponding to the third rotating element RE3 that is integrally connected to the drive gear 26a (see "OUT" in the figure). A second electric motor MG2 (see "MG2" in the drawing) is connected to the driven gear 28, which meshes with the drive gear 26a, via a reduction gear 36 and the like. The mutual intervals between the vertical lines Y1, Y2, and Y3 are determined according to the gear ratio ρ (= number of teeth of the sun gear / number of teeth of the ring gear) of the planetary gear set 40. In the relationship between the vertical axes of the nomographic diagram, if the interval between the sun gear and the carrier corresponds to "1," then the interval between the carrier and the ring gear corresponds to the gear ratio ρ.

[0020] In the transmission unit 24, the relationship between the rotational speed of the sun gear S and the rotational speed of the ring gear R is indicated by the lines Le and Lm that intersect the vertical line Y2. The solid line Le in FIG. 2 indicates an example of the relative speeds of the rotational elements during forward traveling in an HEV traveling mode, which is a traveling mode that allows engine traveling using at least the engine 12 as a power source, i.e., hybrid traveling (=HEV traveling). In the HEV traveling mode, in the planetary gear set 40, an MG1 torque Tg, which is a reaction torque of a negative torque generated by the first electric motor MG1, is input to the sun gear S in response to a positive engine torque Te input to the carrier CA. As a result, a positive engine direct torque Td (=Te / (1+ρ)=-(1 / ρ)×Tg) appears in the ring gear R during forward rotation. Then, the combined torque of the engine direct torque Td and the MG2 torque Tm is transmitted to the drive wheels 14 as a driving torque Tr in the forward direction of the vehicle 10 in accordance with the required driving torque Trdem. In this case, the transmission unit 24 can be operated as an electric continuously variable transmission in which the speed ratio γ (=input rotation speed Ni / output rotation speed No) can be changed continuously. The input rotation speed Ni is the rotation speed of the input shaft 22, and is equal to the engine rotation speed Ne, which is the rotation speed of the engine 12. The output rotation speed No is the rotation speed of the drive gear 26a.

[0021] The dashed line Lm in Fig. 2 shows an example of the relative speeds of the rotating elements during forward travel in BEV travel mode, which is a travel mode that allows motor travel (=BEV travel) using the second electric motor MG2 as a power source with the engine 12 stopped. In BEV travel mode, the first electric motor MG1 is in an unloaded state and is allowed to idle at negative rotation, and the carrier CA is set to zero rotation, i.e., the engine rotation speed Ne is set to zero. In this state, only the second electric motor MG2 is used as a power source, and MG2 torque Tm, which becomes positive torque when transmitted to the driven gear 28 in positive rotation, is transmitted to the drive wheels 14 as drive torque Tr in the forward direction of the vehicle 10.

[0022] Fig. 3 is a diagram illustrating an example of the electrical configuration of an electric circuit unit 60 including an inverter 52 and the like provided in the vehicle 10. In Fig. 3, the vehicle 10 further includes an auxiliary battery 58 and the like in addition to a high-voltage battery 54. The vehicle 10 also further includes an electric circuit unit 60 that controls each of the first electric motor MG1 and the second electric motor MG2.

[0023] The high-voltage battery 54 is a chargeable and dischargeable DC power supply, and is, for example, a secondary battery such as a nickel-metal hydride secondary battery, a lithium-ion battery, etc. The high-voltage battery 54 is connected to the electric circuit unit 60.

[0024] The high-voltage battery 54 supplies stored electric power to the first electric motor MG1 and the second electric motor MG2 via the electric circuit unit 60. Furthermore, electric power resulting from power generation control of the first electric motor MG1 and electric power resulting from regeneration control of the second electric motor MG2 are supplied to the high-voltage battery 54 via the electric circuit unit 60. The high-voltage battery 54 is a drive battery.

[0025] The electric circuit unit 60 includes a DC-DC converter 62, a power control circuit 64, and the like.

[0026] The DC-DC converter 62 is connected to the high-voltage battery 54. The DC-DC converter 62 functions as a charging device that steps down the voltage of the high-voltage battery 54 to a voltage equivalent to that of the auxiliary battery 58 and charges the auxiliary battery 58. The auxiliary battery 58 supplies power to operate the auxiliary devices provided in the vehicle 10. The auxiliary battery 58 also supplies power to operate an electronic control device 90 (described later) and the like.

[0027] The power control circuit 64 includes a boost converter 66 and the inverter 52. The power control circuit 64 controls the power exchanged between the high-voltage battery 54 and the first electric motor MG1 and the second electric motor MG2.

[0028] The boost converter 66 is a step-up / step-down circuit that has the function of boosting the voltage of the high-voltage battery 54 and supplying it to the inverter 52, and the function of reducing the voltage converted to DC by the inverter 52 and supplying it to the high-voltage battery 54.

[0029] The inverter 52 includes an MG1 power module 68, an MG2 power module 70, a capacitor 72, and the like. The MG1 power module 68 includes transistors 74u, 74v, 74w, 76u, 76v, and 76w, and the like. In this embodiment, unless otherwise specified, the transistors 74u, 74v, and 74w are referred to as transistors 74, and the transistors 76u, 76v, and 76w are referred to as transistors 76. The MG1 power module 68 includes transistors 74, 76, and the like, forming a three-phase bridge circuit of U, V, and W phases. The transistors 74 and 76 function as switching elements and are turned on and off to convert DC current into three-phase AC current. The transistor 74 forms the upper arm of the transistors 74 and 76. The transistor 76 forms the lower arm of the transistors 74 and 76. The MG2 power module 70 has a configuration similar to that of the MG1 power module 68, and therefore a description of the MG2 power module 70 will be omitted. The first electric motor MG1 and the second electric motor MG2 are each a three-phase AC synchronous motor driven by an inverter 52 having a plurality of switching elements.

[0030] The inverter 52 converts the DC current from the boost converter 66 into AC current for driving the first electric motor MG1 and the second electric motor MG2. The inverter 52 converts the AC current generated by the first electric motor MG1 using the power of the engine 12 and the AC current generated by the second electric motor MG2 using regenerative braking into DC current. The inverter 52 supplies the AC current generated by the first electric motor MG1 as power for driving the second electric motor MG2 depending on the running state.

[0031] 1, the vehicle 10 is equipped with an electronic control device 90 as a controller including control devices for the vehicle 10 related to the control of the engine 12, electric motors, etc. The electronic control device 90 is configured to include a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The electronic control device 90 performs various controls of the vehicle 10 by having the CPU perform signal processing in accordance with a program stored in advance in the ROM while utilizing the temporary storage function of the RAM.

[0032] The electronic control device 90 is supplied with various signals (e.g., engine rotation speed Ne (= input rotation speed Ni), output rotation speed No corresponding to vehicle speed V, MG1 rotation speed Ng which is the rotation speed of the first electric motor MG1, MG2 rotation speed Nm which is the rotation speed of the second electric motor MG2, accelerator opening θacc, throttle valve opening θth, brake on signal Bon, power switch signal PSon, towing on signal FTon, etc.) based on detection values ​​from various sensors provided on the vehicle 10 (e.g., engine rotation speed sensor 80, output rotation speed sensor 81, MG1 rotation speed sensor 82, MG2 rotation speed sensor 83, accelerator opening sensor 84, throttle valve opening sensor 85, brake switch 86, power switch 87, towing selection switch 88, etc.).

[0033] The power switch 87 is a switch operated by the driver to switch the state of power supply in the vehicle 10, i.e., the vehicle power state. The power switch 87 is, for example, a momentary push button switch, and is pressed to the switch-on position by the driver. Every time the power switch 87 is pressed to the switch-on position, it outputs a power switch signal PSon corresponding to the switch-on position.

[0034] The electronic control unit 90 detects the driver's operation of the power switch 87 based on the power switch signal PSon. The driver's operation of the power switch 87 is a vehicle power operation for switching the vehicle power supply state. The electronic control unit 90 switches the vehicle power supply state in response to the power switch signal PSon, the brake-on signal Bon, etc.

[0035] The vehicle power supply states include, for example, an off (= "OFF") state, an accessory on (= "ACC") state, an ignition on (= "IG-ON") state, and a ready on (= "READY-ON") state. The OFF state is, for example, a power supply state in which the vehicle is disabled from traveling and some functions not related to vehicle traveling are also disabled. The ACC state is, for example, a power supply state in which a combination meter (not shown) is turned off to disable vehicle traveling but some functions not related to vehicle traveling are enabled. The IG-ON state is, for example, a power supply state in which the combination meter is turned on to enable control of functions other than those controlling vehicle traveling. The IG-ON state is a power supply state in which a driving torque Tr cannot be generated, i.e., a power supply state in which the vehicle 10 cannot start or travel even when the accelerator is depressed. In other words, the IG-ON state is a predetermined vehicle power supply state in which the engine 12 cannot be put into operation and the vehicle 10 cannot be driven. The READY-ON state is, for example, a power supply state in which the combination meter is turned on to enable vehicle traveling. That is, the READY-ON state is a power supply state in which vehicle running can be controlled, and the vehicle 10 can start and run when the accelerator is turned on.

[0036] The towing selection switch 88 is a switch operated by the driver to select flat towing mode. Flat towing mode is a driving style of the vehicle 10 that corresponds to towed driving in which the vehicle 10 is towed. Towed driving in flat towing mode is, for example, flat towing in which the vehicle 10 is towed with the engine stopped and all wheels of the vehicle 10 on the ground. Flat towing is used, for example, when the vehicle 10 is hitched to a camper or motor home and traveling, and is also called "four-down towing," "dinghy towing," "recreational towing," etc. The towing selection switch 88 is, for example, a dial-type changeover switch, and when the driver switches it to the flat towing selection position, it outputs a towing-on signal FTon.

[0037] The electronic control device 90 outputs various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Smg for controlling each of the first electric motor MG1 and the second electric motor MG2, etc.) to each device (e.g., an engine control device 50, an inverter 52, etc.) provided in the vehicle 10.

[0038] The electronic control device 90 includes a power source control means, i.e., a power source control section 92, and a towing control means, i.e., a towing control section 94, in order to realize various controls in the vehicle 10.

[0039] The power source control unit 92 includes an engine control function for controlling the operation of the engine 12 and an electric motor control function for controlling the operation of the first electric motor MG1 and the second electric motor MG2 via the inverter 52.

[0040] The power source control unit 92 calculates the amount of driving demanded by the driver for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand map. The driving demand map is a relationship for calculating the amount of driving demand that is determined and stored in advance experimentally or by design, i.e., a predetermined relationship. The amount of driving demand is, for example, the driving torque Tr required for the vehicle 10, i.e., the required driving torque Trdem [Nm] at the drive wheels 14. In other words, the required driving torque Trdem is the required driving power Prdem [W] at the vehicle speed V at that time. The amount of driving demand can also be the required driving force Frdem [N] at the drive wheels 14, or the like.

[0041] The power source control unit 92 outputs an engine control command signal Se and an MG control command signal Smg to realize the required drive power Prdem, taking into account, for example, transmission loss, auxiliary load, and the like. For example, the engine control command signal Se is a command value for engine power Pe, which is the power of the engine 12 that outputs engine torque Te at the engine rotation speed Ne at that time, taking into account the engine optimal fuel efficiency point, etc. The MG control command signal Smg is a command value for the generated power Wg of the first electric motor MG1 that outputs MG1 torque Tg at the MG1 rotation speed Ng when a command is output as a reaction torque of the engine torque Te. The MG control command signal Smg is a command value for the consumed power Wm of the second electric motor MG2 that outputs MG2 torque Tm at the MG2 rotation speed Nm when a command is output for the generated power Wg. The engine optimal fuel efficiency point is predetermined as an engine operating point that maximizes the total fuel efficiency of the vehicle 10, taking into account, for example, the fuel efficiency of the engine 12 alone, the charge / discharge efficiency of the high-voltage battery 54, the transmission efficiency of the power transmission device 16, and the like.

[0042] When the required driving power Prdem is in a BEV driving range where the required driving power Prdem is less than a predetermined threshold, the power source control unit 92 sets the driving mode of the vehicle 10 to the BEV driving mode. On the other hand, when the required driving power Prdem is in an HEV driving range where the required driving power Prdem is equal to or greater than a predetermined threshold, the power source control unit 92 sets the driving mode of the vehicle 10 to the HEV driving mode. On the other hand, even when the required driving power Prdem is in the BEV driving range, the power source control unit 92 establishes the HEV driving mode when the high-voltage battery 54 needs to be charged or the engine 12 or the like needs to be warmed up.

[0043] When the towing-on signal FTon is output, the towing control unit 94 turns on the flat towing mode flag. When the towing control unit 94 turns on the flat towing mode flag, it sets the vehicle power supply state to IG-ON and sets the transmission unit 24 to neutral. Flat towing is performed with the transmission unit 24 in neutral. The neutral state of the transmission unit 24 is achieved, for example, by causing the first electric motor MG1 to idle in an unloaded state and not generating a reaction torque to the engine torque Te, thereby making the transmission unit 24 unable to transmit the engine torque Te.

[0044] When flat towing is occurring, the drive gear 26a rotates as the drive wheels 14 rotate, making it necessary to lubricate the planetary gear unit 40 and other components. Meanwhile, when flat towing is occurring, the engine 12 is stopped and the input shaft 22 is not rotating, so the MOP 56 is not driven and oil Fld for lubricating the planetary gear unit 40 and other components is not supplied. Meanwhile, when flat towing is occurring, the vehicle power supply is in the IG-ON state, making it impossible to start the engine 12. Therefore, if the vehicle 10 does not have an electric oil pump, there is a risk that the oil Fld for lubricating the planetary gear unit 40 and other components will run short if flat towing continues for a long period of time or over a long distance.

[0045] During flat towing, the transmission 24 is in a neutral state, and the rotation of the drive gear 26a is constrained by the rotation of the drive wheels 14. Therefore, if the first electric motor MG1 is controlled to stop its rotation during flat towing, the input shaft 22 is rotated, and the electric oil pump can be driven.

[0046] The towing control unit 94 outputs an MG control command signal Smg for executing motor stop control, i.e., MG1 stop control CTstmg1, to control the first electric motor MG1 to stop rotation of the first electric motor MG1 while flat towing is being performed. The towing control unit 94 executes the MG1 stop control CTstmg1 for a predetermined time TMf at predetermined intervals IVf while flat towing is being performed. The predetermined time TMf is a predetermined control time for ensuring a sufficient supply of oil Fld for lubricating the planetary gear unit 40, etc.

[0047] The predetermined interval IVf is, for example, every time the cumulative time TMcnt when flat towing is performed reaches a predetermined cumulative time TMcntf, or every time the cumulative distance DTcnt when flat towing is performed reaches a predetermined cumulative distance DTcntf. A time when flat towing is performed is, for example, when the vehicle is traveling with the flat towing mode selected, that is, when the vehicle is traveling with the flat towing mode on. Alternatively, a time when flat towing is performed is, for example, when the vehicle is traveling in a vehicle state similar to that in flat towing mode, that is, when the vehicle power supply is IG-ON and the vehicle speed V exceeds a predetermined vehicle speed Vf. The predetermined vehicle speed Vf is, for example, a predetermined lower limit vehicle speed for determining that the vehicle 10 is moving due to flat towing.

[0048] The cumulative time TMcnt is a numerical value obtained by measuring the travel time during flat towing, i.e., a continuous time count. The cumulative distance DTcnt is a numerical value obtained by measuring the travel distance during flat towing, i.e., a continuous distance count. The predetermined cumulative time TMcntf and the predetermined cumulative distance DTcntf are each predetermined thresholds for determining whether lubrication of the planetary gear unit 40, etc. is necessary. After executing the MG1 stop control CTstmg1, the towing control unit 94 clears the cumulative time TMcnt and resets it to zero, and also clears the cumulative distance DTcnt and resets it to zero.

[0049] The MG1 stop control CTstmg1 is, for example, three-phase on control of the MG1 power module 68 of the inverter 52, i.e., MG1 three-phase on control CTonmg1. The towing control unit 94 executes the MG1 three-phase on control CTonmg1 by controlling the inverter 52 to turn on both upper arms (transistors 74) of the transistors 74, 76 and to turn off both lower arms (transistors 76). Alternatively, the towing control unit 94 executes the MG1 three-phase on control CTonmg1 by controlling the inverter 52 to turn off both upper arms of the transistors 74, 76 and to turn on both lower arms. If the MG1 three-phase on control CTonmg1 is executed while the first electric motor MG1 is rotating, the first electric motor MG1 generates drag torque, which stops the rotation of the first electric motor MG1. The drag torque of the first electric motor MG1 is a torque that decreases the absolute value of the MG1 rotation speed Ng.

[0050] FIG. 4 is a diagram illustrating the MG1 three-phase on control CTonmg1. FIG. 4 shows an example of the relative speeds of the rotating elements during flat towing when the MG1 three-phase on control CTonmg1 is not being executed, in a nomographic chart similar to FIG. 2 . When the MG1 three-phase on control CTonmg1 is not being executed, the first electric motor MG1 is idling under no load, thereby stopping the rotation of the carrier CA, i.e., the input shaft 22. Meanwhile, the solid line Lon shows an example of the relative speeds of the rotating elements during flat towing when the MG1 three-phase on control CTonmg1 is being executed. When the MG1 three-phase on control CTonmg1 is being executed, the first electric motor MG1, which had been idling, generates drag torque, causing the rotation of the first electric motor MG1 to stop. This rotates the input shaft 22 and drives the MOP 56, supplying oil Fld for lubricating the planetary gear unit 40 and the like.

[0051] The MG1 three-phase on control CTonmg1 is a control for generating a braking torque resulting from the back electromotive force of the rotating first electric motor MG1 to decelerate the first electric motor MG1, and is not a control for outputting a positive or negative MG1 torque Tg. The MG1 three-phase on control CTonmg1 is not a control for outputting a torque for cranking the engine 12 by the first electric motor MG1. Therefore, the MG1 three-phase on control CTonmg1 can be executed even when the high-voltage battery 54 is disconnected from the electric circuit unit 60 by a relay (not shown). When the vehicle power supply state is IG-ON, for example, the high-voltage battery 54 is disconnected from the electric circuit unit 60 by a relay (not shown).

[0052] FIG. 5 is a flowchart illustrating the main control operations of the electronic control device 90, which are for lubricating the planetary gear unit 40 and the like using the MOP 56 during flat towing, and which are executed repeatedly, for example.

[0053] In FIG. 5, each step in the flowchart corresponds to a function of the towing control unit 94. In step (hereinafter, "step" will be omitted) S10, it is determined whether the flat towing mode is on, or whether the vehicle power supply state is IG-ON and the vehicle speed V exceeds a predetermined vehicle speed Vf. If the determination in S10 is negative, the routine is terminated. If the determination in S10 is positive, the accumulated time TMcnt, which is a count of the duration of flat towing, is updated in S20, and the accumulated distance DTcnt, which is a count of the continuous distance of flat towing, is updated. Next, in S30, it is determined whether the accumulated time TMcnt has exceeded a predetermined accumulated time TMcntf, or whether the accumulated distance DTcnt has exceeded a predetermined accumulated distance DTcntf. If the determination in S30 is negative, the routine is terminated. If the determination in S30 is positive, the MG1 three-phase ON control CTonmg1 is performed for a predetermined time TMf in S40. In addition, the accumulated time TMcnt is cleared. In addition, the cumulative distance DTcnt is cleared.

[0054] As described above, the MG1 stop control CTstmg1 is executed for the predetermined time TMf each time the accumulated time TMcnt during flat towing reaches the predetermined accumulated time TMcntf, or each time the accumulated distance DTcnt during flat towing reaches the predetermined accumulated distance DTcntf. As a result, in the planetary gear set 40, the rotation of the second rotating element RE2 is stopped while the third rotating element RE3 is rotated, so that the first rotating element RE1 is rotated and the MOP 56 is rotationally driven. Therefore, the planetary gear set 40 and the like can be lubricated using the MOP 56 during flat towing.

[0055] Furthermore, according to this embodiment, flat towing is performed with the transmission unit 24 in a neutral state, with the first electric motor MG1 idling under no load. This allows flat towing to be performed appropriately. Furthermore, the MOP 56 is appropriately rotated by the MG1 stop control CTstmg1 during flat towing.

[0056] Furthermore, according to this embodiment, flat towing occurs when the vehicle is traveling with the vehicle power supply in the IG-ON state and the vehicle speed V exceeding a predetermined vehicle speed Vf, or when the vehicle is traveling with the flat towing mode selected. This allows lubrication of the planetary gear unit 40 and the like using the MOP 56 during flat towing.

[0057] Furthermore, according to this embodiment, the MG1 stop control CTstmg1 is the MG1 three-phase on control CTonmg1, so that the rotation of the first electric motor MG1 is appropriately stopped during flat towing.

[0058] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0059] For example, in the above-described embodiment, the towed traveling of the vehicle 10 for which the MG1 stop control CTstmg1 is executed is not limited to flat towing. For example, even when the vehicle 10 is towed in a state where only the drive wheels 14 are in contact with the ground and the driven wheels are not in contact with the ground, the drive gear 26a is rotated, and therefore the planetary gear unit 40 and the like must be lubricated. Therefore, the towed traveling of the vehicle 10 for which the MG1 stop control CTstmg1 is executed may be when the engine 12 is stopped and the drive wheels 14 are in contact with the ground.

[0060] Furthermore, in the above-described embodiments, the present invention can be applied to any vehicle equipped with an electric transmission mechanism including a differential mechanism having at least three rotating elements.

[0061] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0062] 10: Vehicle 12: Engine 14: Drive wheels 22: Input shaft (input rotating member) 24: Transmission unit (electric transmission mechanism) 40: Planetary gear device (differential mechanism) CA: Carrier (RE1: first rotating element) S: Sun gear (RE2: second rotating element) R: Ring gear (RE3: third rotating element) 52: Inverter 56: Mechanical oil pump 74 (74u, 74v, 74w): Transistor (switching element, upper arm) 76 (76u, 76v, 76w): Transistor (switching element, lower arm) 90: Electronic control unit (control unit) Fld: Oil MG1: First electric motor (electric motor)

Claims

1. a control device for a vehicle comprising: an engine; an input rotating member to which the engine is connected so as to be able to transmit power; an electric transmission mechanism having a differential mechanism to which power from the engine is input via the input rotating member and an electric motor connected so as to be able to transmit power to the differential mechanism, wherein a differential state of the differential mechanism is controlled by controlling an operating state of the electric motor; and a mechanical oil pump that is driven in conjunction with rotation of the input rotating member to supply oil that lubricates the differential mechanism, wherein the differential mechanism includes a first rotating element connected so as to be able to transmit power to the input rotating member, a second rotating element to which the electric motor is connected so as to be able to transmit power, and a third rotating element connected so as to be able to transmit power to drive wheels, the electric motor is a three-phase AC electric motor driven by an inverter having a plurality of switching elements, an electric motor stop control for controlling the electric motor to stop rotation is executed for a predetermined time each time an accumulated time during towed running in which the vehicle is towed with the engine stopped and the drive wheels in contact with the ground reaches a predetermined accumulated time, or each time an accumulated distance during towed running reaches a predetermined accumulated distance, and after the electric motor stop control is executed, the accumulated time and the accumulated distance are reset to zero; The vehicle control device, wherein the motor stop control is a three-phase ON control that controls the inverter so that either one of the upper arms or one of the lower arms of the switching elements is turned ON.

2. 2. The vehicle control device according to claim 1, wherein the towed traveling is performed in a neutral state of the electric transmission mechanism in which the electric motor is rotated idly under no load.

3. The vehicle control device described in claim 1, characterized in that the towed driving is performed when the vehicle is driven in a predetermined vehicle power state in which the power supply state in the vehicle cannot put the engine into an operating state and the vehicle cannot be driven, and the vehicle speed exceeds a predetermined vehicle speed, or when the vehicle is driven in a state in which a driving mode corresponding to the towed driving is selected.

4. 2. The vehicle control device according to claim 1, wherein the towed traveling is flat towing, in which the vehicle is towed with all wheels of the vehicle in contact with the ground.

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