JP2016084077A - Vehicular drive apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of cavitation in a hybrid vehicle that includes both of a transmission and a power distribution device disposed between an engine and first and second rotary electric machines, and an oil pump driven by an output shaft of the transmission.SOLUTION: A vehicle 1 travels on drive force of at least any of an engine 10, and first and second MG 20, 30. A drive apparatus of the vehicle includes: a transmission 40 connected to an output shaft of the engine; a power distribution device 50 for transmitting rotation from the transmission to a drive wheel; an oil pump 62 driven by an output shaft of the transmission; and an ECU 300. In the case of a rotation speed of the oil pump increasing to a given threshold in an HV travel mode the ECU increases a gear ratio of the transmission and adjusts a rotation speed of the first MG so that a rotation speed of the drive wheel is maintained when the gear ratios are changed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle drive device, and more particularly to a drive device for a vehicle that travels using the output of at least one of an internal combustion engine and first and second rotating electrical machines.

  A hybrid vehicle having a configuration in which a transmission and a power distribution device are provided between an internal combustion engine (engine) and first and second rotating electrical machines (motor generators) is known. For example, in a hybrid vehicle disclosed in International Publication No. 2013/114594 (Patent Document 1), a planetary gear mechanism having a carrier, a sun gear, and a ring gear is used as a power distribution device. The carrier is coupled to the engine via a transmission. The sun gear is coupled to the first rotating electric machine. The ring gear is coupled to the counter shaft, and the second rotating electrical machine and the output shaft are connected to the counter shaft.

  In the hybrid vehicle disclosed in Patent Document 1, in the hybrid (HV) travel mode in which the vehicle travels using the driving force of the engine, the engine and the first rotating electrical machine transmitted via the transmission and the power distribution device are used. The driving force and the driving force from the second rotating electrical machine are transmitted to the counter shaft, and the vehicle travels by these combined driving forces.

International Publication No. 2013/114594 JP2013-249046A JP 2005-76542 A

  A vehicle having a configuration in which a mechanical oil pump is connected to an output shaft of a transmission (that is, a carrier of a power distribution device) is known. This mechanical oil pump supplies hydraulic pressure necessary for lubrication and cooling of the drive device, and is driven by the rotation of the engine. The rotational speed of the mechanical oil pump varies not only with the rotational speed of the engine but also with the gear ratio of the transmission.

  In particular, when the high speed gear ratio is selected, the rotational speed of the mechanical oil pump is higher than when the low speed gear ratio is selected, and the amount of discharged oil increases accordingly. However, if the rotational speed of the mechanical oil pump becomes too high, there is a possibility that cavitation in which bubbles are generated in the oil passage may occur.

  On the other hand, in a hybrid vehicle, the engine is generally driven at an operating point at which fuel efficiency is optimal while achieving a desired required power. Therefore, if the operating point (rotational speed) of the engine is changed in order to prevent the occurrence of cavitation, the efficiency of the engine may be deteriorated.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a transmission and a power distribution device between the engine and the first and second rotating electrical machines, and the transmission. In a hybrid vehicle having an oil pump driven by the output shaft, cavitation is prevented while suppressing deterioration of fuel consumption of the engine.

  A vehicle drive device according to the present invention is a drive device for driving a vehicle that travels by using a driving force of at least one of an internal combustion engine and first and second rotating electrical machines. The drive device controls a transmission coupled to the output shaft of the internal combustion engine, a power distribution device, an oil pump driven by the output shaft of the transmission, the first and second rotating electric machines, and the transmission. Control device. The power distribution device is coupled to the output shafts of the first and second rotating electrical machines and the output element of the transmission, and transmits the driving force from the first and second rotating electrical machines and the transmission to the drive wheels. In the travel mode in which the control device travels using the driving force from the internal combustion engine and the driving force from the second rotating electrical machine, when the rotational speed of the oil pump increases to a predetermined threshold value, the control device The transmission is controlled so that the gear ratio becomes larger, and the rotational speed of the first rotating electrical machine is adjusted so that the rotational speed of the drive wheels is maintained when the gear ratio is changed.

  By adopting such a configuration, when the rotation speed of the oil pump increases to an upper limit (threshold value) determined from the occurrence of cavitation, the transmission device is moved to the lower speed side so that the gear ratio becomes larger. By shifting the speed, the rotational speed of the oil pump can be reduced without changing the operating point of the engine.

  In addition, by appropriately adjusting the rotation speed of the first rotating electrical machine during the speed change operation, it is possible to suppress fluctuations in the rotation speed of the drive wheels accompanying the speed change operation.

  According to the present invention, in a hybrid vehicle having an oil pump that is provided with a transmission and a power distribution device between the engine and the first and second rotating electrical machines and that is driven by the output shaft of the transmission, the fuel consumption of the engine It is possible to prevent the occurrence of cavitation while suppressing the deterioration of.

FIG. 2 is a skeleton diagram of a vehicle on which a drive device according to the first embodiment is mounted. It is a figure which shows the operation engagement table | surface of the clutch C1 and brake B1 which are included in a transmission. It is an alignment chart in the HV traveling mode when the transmission is on the Lo side. It is an alignment chart in the HV running mode when the transmission is on the Hi side. It is an alignment chart in the single motor travel mode. It is a collinear diagram in both motor drive modes. It is a figure for demonstrating the driving mode selected according to a request | requirement driving force and a vehicle speed. FIG. 6 is a collinear diagram for illustrating a shift control for suppressing cavitation according to the first embodiment. In Embodiment 1, it is a functional block diagram for demonstrating the shift control performed by ECU. It is a figure for demonstrating the relationship between oil temperature and the upper limit rotational speed of the oil pump which considered generation | occurrence | production of cavitation. 4 is a flowchart for illustrating details of a shift control process executed by an ECU in the first embodiment. It is a skeleton figure of the vehicle by which the drive device according to Embodiment 2 is mounted.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
(Basic configuration of vehicle)
FIG. 1 is a skeleton diagram showing an overall configuration of a vehicle 1 on which a drive device according to the first embodiment is mounted. The drive device of the vehicle 1 includes an engine 10, a first motor generator (hereinafter referred to as “first MG”) 20, a second motor generator (hereinafter referred to as “second MG”) 30, a first MG, and a second MG. Inverters 25 and 35 for driving, a transmission 40, a power distribution device (planetary gear device) 50, a counter shaft (output shaft) 70, a differential device 80, a drive wheel 90, an ECU (Electronic Control) Unit) 300.

  The vehicle 1 is an FF (front engine / front drive) type hybrid vehicle that travels using at least one of the power of the engine 10, the first MG 20, and the second MG 30. The driving method of the vehicle 1 is not limited to the FF method, and may be an FR (front engine / rear drive) method. The vehicle 1 may be a plug-in hybrid vehicle that can charge an in-vehicle battery (not shown) with an external power source.

  The engine 10 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine. Engine 10 is controlled by a control signal DRV from ECU 300.

  The first MG 20 and the second MG 30 are, for example, permanent magnet type synchronous motors including a rotor in which permanent magnets are embedded. The rotation shaft 21 of the first MG 20 is disposed coaxially with the crankshaft of the engine 10. The rotation shaft 31 of the second MG 30 is arranged in parallel with the rotation shaft 21 of the first MG 20. The counter shaft (output shaft) 70 is arranged in parallel with the rotation shaft 21 of the first MG 20 and the rotation shaft 31 of the second MG 30.

  First MG 20 and second MG 30 are driven by inverters 25 and 35, respectively. The inverter 25 is controlled by a control signal PWI1 from the ECU 300, converts DC power from a vehicle battery (not shown) into AC power, and supplies the AC power to the first MG 20. Similarly, inverter 35 is controlled by control signal PWI2 from ECU 300, converts DC power from the battery into AC power, and supplies the AC power to second MG 30. The second MG 30 is also driven by the electric power generated by the first MG 20.

  The transmission 40 is provided between the engine 10 and a power distribution device (planetary gear device) 50, and changes the rotation of the engine 10 to output it to the power distribution device 50. The transmission 40 includes a single pinion planetary gear mechanism including a sun gear S1, a pinion gear P1, a ring gear R1, and a carrier CA1, a clutch C1, and a brake B1.

  Carrier CA1 is coupled to the crankshaft of engine 10. The pinion gear P1 is disposed between the sun gear S1 and the ring gear R1, and meshes with the sun gear S1 and the ring gear R1, respectively. Pinion gear P1 is supported by carrier CA1 so as to be capable of rotating and revolving.

  The rotational speed of the sun gear S1, the rotational speed of the carrier CA1 (that is, the rotational speed of the engine 10), and the rotational speed of the ring gear R1 are connected in a straight line on the collinear chart as shown in FIGS. If any two rotation speeds are determined, the remaining rotation speed is also determined).

  The clutch C1 is a hydraulic friction engagement element capable of connecting the sun gear S1 and the carrier CA1. When the clutch C1 is engaged, the sun gear S1 and the carrier CA1 are connected. When the clutch C1 is released, the sun gear S1 and the carrier CA1 are disconnected.

  The brake B1 is a hydraulic friction engagement element that can restrict (lock) the rotation of the sun gear S1. When the brake B1 is engaged, the sun gear S1 is fixed to the gear case (vehicle body), so that the rotation of the sun gear S1 is restricted. When the brake B1 is released, the sun gear S1 is disconnected from the gear case (vehicle body), so that the sun gear S1 is allowed to rotate.

  The speed ratio of the transmission 40 (the ratio between the rotational speed of the carrier CA1 as an input element and the rotational speed of the ring gear R1 as an output element, specifically, the rotational speed of the carrier CA1 / the rotational speed of the ring gear R1) is determined by the clutch C1. And switching according to the combination of engagement and release of the brake B1. When the clutch C1 is engaged and the brake B1 is released, a low gear stage Lo having a gear ratio of 1.0 (directly connected state) is formed. When the clutch C1 is released and the brake B1 is engaged, a high gear stage Hi is formed in which the gear ratio becomes a value smaller than 1.0 (for example, 0.7, so-called overdrive state). Note that when the clutch C1 is engaged and the brake B1 is engaged, the rotation of the sun gear S1 and the carrier CA1 is restricted, so that the rotation of the ring gear R1 is also restricted. In the present embodiment, the case where the transmission 40 switches between two gear stages, the low gear stage Lo and the high gear stage Hi, will be described as an example. However, the transmission apparatus 40 switches between three or more gear stages. It is also possible to change the gear ratio continuously.

  The power distribution device 50 is a single pinion type planetary gear device including a sun gear S2, a pinion gear P2, a ring gear R2, and a carrier CA2. The carrier CA2 of the power distribution device 50 is connected to the ring gear R1 that is an output element of the transmission 40, and rotates integrally with the ring gear R1.

  Pinion gear P2 is arranged between sun gear S2 and ring gear R2, and meshes with sun gear S2 and ring gear R2, respectively. Pinion gear P2 is supported by carrier CA2 so as to be capable of rotating and revolving.

  Sun gear S2 is coupled to rotating shaft 21 of first MG 20. A counter drive gear 51 is connected to the ring gear R2. The counter drive gear 51 is an output gear of the power distribution device 50 that rotates integrally with the ring gear R2.

  The rotational speed of the sun gear S2 (that is, the rotational speed of the first MG 20), the rotational speed of the carrier CA2, and the rotational speed of the ring gear R2, as shown in FIGS. If any two rotation speeds are determined, the remaining rotation speed is also determined). Therefore, by adjusting the rotation speed of the first MG 20, the ratio between the rotation speed of the carrier CA2 and the ring gear R2 can be switched steplessly.

  The counter shaft (output shaft) 70 is provided with a counter driven gear 71 and a differential drive gear 72. Counter driven gear 71 meshes with counter drive gear 51 of power distribution device 50. That is, the power of the engine 10 and the first MG 20 is transmitted to the counter shaft (output shaft) 70 via the counter drive gear 51 of the power distribution device 50.

  The transmission 40 and the power distribution device 50 are connected in series on a power transmission path from the engine 10 to the counter shaft (output shaft) 70. Therefore, the rotation of the engine 10 is transmitted to the counter shaft (output shaft) 70 after being shifted by the transmission 40 and the power distribution device 50.

  Counter driven gear 71 also meshes with reduction gear 32 connected to rotating shaft 31 of second MG 30. That is, the power of the second MG 30 is transmitted to the counter shaft (output shaft) 70 via the reduction gear 32.

  The differential drive gear 72 meshes with the differential ring gear 81 of the differential device 80. The differential device 80 is connected to the left and right drive wheels 90 via left and right drive shafts 82, respectively. That is, the rotation of the counter shaft (output shaft) 70 is transmitted to the left and right drive shafts 82 via the differential device 80.

  The vehicle 1 includes an oil pump 62 and a hydraulic circuit 63 as a configuration for driving the transmission 40.

  The rotation shaft 65 of the oil pump 62 is connected to a gear 64 provided on a ring gear R1 that is an output shaft of the transmission 40 via a one-way clutch F1. Thus, when the engine 10 is driven, the oil pump 62 is driven and the hydraulic pressure is supplied to the hydraulic circuit 63. That is, the oil pump 62 functions as a mechanical oil pump (hereinafter also referred to as “MOP”) driven by the engine 10.

  The rotation shaft 65 of the oil pump 62 is also connected to a gear 66 provided on the output shaft 67 of the motor 61 via the one-way clutch F2. For example, when the vehicle 1 travels in a “motor travel mode (hereinafter referred to as“ EV travel mode ”) that travels with at least one driving force of the first MG 20 or the second MG 30 with the engine 10 stopped, As will be described later, the ring gear R1 of the transmission 40 is stopped, and the oil pump 62 may not be driven by the engine 10. In such a case, the motor 61 is driven by the control command SE1 from the ECU 300, and the oil pump 62 is driven by the motor 61. That is, in this case, the oil pump 62 functions as an electric oil pump (hereinafter also referred to as “EOP”) driven by the motor 61. As a result, even when the engine 10 is stopped, the hydraulic pressure can be supplied to the hydraulic circuit 63.

  As shown in FIG. 1, by using the one-way clutches F <b> 1 and F <b> 2, the oil pump 62 operates using the driving force that increases the rotational speed of the ring gear R <b> 1 and the motor 61. For example, even when the vehicle is traveling in the “hybrid traveling mode (hereinafter referred to as“ HV traveling mode ”), the oil pump 62 can be operated as an electric oil pump by driving the motor 61. Note that the electric oil pump may be provided independently of the mechanical oil pump.

  The hydraulic circuit 63 includes solenoid valves that respectively adjust the hydraulic pressure supplied to the clutch C1 and the brake B1 of the transmission 40 using the hydraulic pressure supplied from the oil pump 62 as a source pressure. Each solenoid valve in the hydraulic circuit 63 is controlled by control signals PbC and PbB from the ECU 300.

  ECU 300 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer, all of which are not shown in FIG. 1, and inputs signals from sensors and the like and outputs control signals to each device. 1 and each device are controlled. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  The ECU 300 causes the vehicle 1 to travel in the “hybrid travel mode (HV travel mode)” or “motor travel mode (EV travel mode)”. The HV travel mode is a control mode in which the vehicle 1 travels with the power of the engine 10 and the second MG 30. The EV travel mode is a control mode in which the engine 10 is stopped and the vehicle 1 is traveled by at least one power of the first MG 20 or the second MG 30 as described above. During the EV travel mode, ECU 300 travels vehicle 1 with the power of the second MG 30 alone and “both motor travel mode” with vehicle 1 traveling with the power of both first MG 20 and second MG 30. Are selectively switched according to a user's required torque or the like.

  FIG. 2 is a diagram showing an operation engagement table of the clutch C1 and the brake B1 of the transmission 40 in each travel mode. In FIG. 2, “C1”, “B1”, “MG1”, and “MG2” indicate the clutch C1, the brake B1, the first MG20, and the second MG30, respectively. The circles (◯) in the C1 and B1 columns indicate “engaged”, the “×” indicates “released”, and the triangle (Δ) indicates either the clutch C1 or the brake B1 during engine braking. Indicates that Further, “G” in the MG1 column and MG2 column indicates that the operation is performed as a generator, and “M” indicates that the operation is performed as a motor.

  In the HV traveling mode, ECU 300 switches the gear ratio of transmission 40 according to the vehicle speed. When the vehicle 1 is moved forward in the medium / low speed range or when the vehicle 1 is moved backward, the ECU 300 forms the low gear stage Lo by engaging the clutch C1 and releasing the brake B1 (see FIG. 3 described later). On the other hand, when the vehicle 1 is advanced in the high speed range, the ECU 300 releases the clutch C1 and engages the brake B1 to form the high gear stage Hi (see FIG. 4 described later). Further, in the engine travel mode, ECU 300 operates first MG 20 as a generator and operates second MG 30 as a motor.

  In the HV traveling mode, since the engine 10 is operating, the oil pump 62 is driven by the engine 10.

  In the EV travel mode, the ECU 300 selectively switches between the single motor travel mode and the both motor travel mode as described above. When the vehicle 1 is driven (forward or reverse) in the single motor travel mode, the ECU 300 releases the clutch C1 and releases the brake B1 to place the transmission 40 in a neutral state (a state in which no power is transmitted). When the vehicle 1 is braked in the single motor traveling mode and the engine brake is necessary, the ECU 300 engages one of the clutch C1 and the brake B1. As a result, the rotation of the drive wheel 90 is transmitted to the engine 10, thereby causing a so-called engine brake state in which the engine 10 is rotated. In the single motor travel mode, ECU 300 operates first MG 20 as a generator and operates second MG 30 as a motor (see FIG. 5 described later).

  On the other hand, when the vehicle 1 is driven (forward or reverse) in the dual motor travel mode, the ECU 300 engages the clutch C1 and engages the brake B1 to restrict (lock) the rotation of the ring gear R1 of the transmission 40. . Accordingly, the rotation of the carrier CA2 of the power distribution device 50 connected to the ring gear R1 of the transmission 40 is also restricted (locked), so that the carrier CA2 of the power distribution device 50 is maintained in a stopped state. Then, ECU 300 operates first MG 20 and second MG 30 as motors (see FIG. 6 described later).

  In the both-motor travel mode in the EV travel mode, the engine 10 is stopped and the ring gear R1 is also stopped, so the oil pump 62 cannot be driven by the engine 10. Therefore, the oil pump 62 is driven by the motor 61 in the both-motor running mode.

(Explanation of driving mode)
3 to 6 are collinear charts during the HV traveling mode (Lo / Hi), during the single motor traveling mode, and during both motor traveling modes, respectively. 3 to 6, “S1”, “CA1”, and “R1” respectively indicate the sun gear S1, the carrier CA1, and the ring gear R1 of the transmission 40, and “S2”, “CA2”, and “R2” respectively indicate the power distribution device. 50 sun gear S2, carrier CA2, and ring gear R2 are shown. The oil pump 62 is connected to the ring gear R1 and the carrier CA2.

  With reference to FIG. 3, the control state when traveling forward at the low gear stage Lo in the HV traveling mode will be described. When the low gear stage Lo is formed, the clutch C1 is engaged and the brake B1 is released. Therefore, the rotation elements S1, CA1, and R1 rotate together. Thereby, the ring gear R1 of the transmission 40 also rotates at the same rotational speed as the carrier CA1, and the rotation of the engine 10 is transmitted from the ring gear R1 to the carrier CA2 of the power distribution device 50 at the same rotational speed. That is, the torque of the engine 10 (hereinafter referred to as “engine torque Te”) input to the carrier CA1 of the transmission 40 is transmitted from the ring gear R1 of the transmission 40 to the carrier CA2 of the power distribution device 50. The torque output from the ring gear R1 (hereinafter referred to as “transmission unit output torque Tr1”) is the same as the engine torque Te (Te = Tr1).

  The rotation of the engine 10 transmitted to the carrier CA2 of the power distribution device 50 is steplessly changed by the rotation speed of the sun gear S2 (rotation speed of the first MG 20) and transmitted to the ring gear R2 of the power distribution device 50. At this time, ECU 300 operates first MG 20 as a generator, and causes torque of first MG 20 (hereinafter referred to as “first MG torque Tm1”) to act in the negative direction. As a result, the first MG torque Tm1 takes charge of the reaction force for transmitting the engine torque Te input to the carrier CA2 to the ring gear R2.

  Engine torque Te transmitted to ring gear R2 (hereinafter referred to as “engine transmission torque Tec”) is transmitted from counter drive gear 51 to counter shaft (output shaft) 70 and acts as a driving force for vehicle 1.

  Further, in the HV traveling mode, ECU 300 operates second MG 30 as a motor. Torque of the second MG 30 (hereinafter referred to as “second MG torque Tm2”) is transmitted from the reduction gear 32 to the counter shaft (output shaft) 70 and acts as a driving force of the vehicle 1. That is, in the HV traveling mode, the vehicle 1 travels using the engine transmission torque Tec and the second MG torque Tm2.

  FIG. 4 illustrates a case where the vehicle is traveling forward at the high gear stage Hi in the HV traveling mode. Since the brake B1 is engaged when the high gear stage Hi is formed, the rotation of the sun gear S1 is restricted. Thus, the rotation of the engine 10 input to the carrier CA1 of the transmission 40 is increased and transmitted from the ring gear R1 of the transmission 40 to the carrier CA2 of the power distribution device 50. Therefore, the transmission output torque Tr1 is smaller than the engine torque Te (Te> Tr1).

  As shown in the nomographs of FIGS. 3 and 4, in the HV traveling mode, the ring gear R1 is driven by the engine 10, so that the oil pump 62 operates as a mechanical oil pump.

  Next, the control state during the single motor travel mode will be described with reference to FIG. In the single motor travel mode, ECU 300 stops engine 10 and operates second MG 30 as a motor. Therefore, in the single motor travel mode, the vehicle 1 travels using the second MG torque Tm2.

  At this time, ECU 300 feedback-controls first MG torque Tm1 so that the rotational speed of sun gear S1 becomes zero. Therefore, the sun gear S1 does not rotate. However, since the clutch C1 and the brake B1 of the transmission 40 are released, the rotation of the carrier CA2 of the power distribution device 50 is not restricted. Therefore, ring gear R2 of power distribution device 50, carrier CA2 and ring gear R1 of transmission 40 are rotated (idled) in the same direction as the rotation direction of second MG 30 in conjunction with the rotation of second MG 30.

  On the other hand, the carrier CA1 of the transmission 40 is maintained in a stopped state when the engine 10 is stopped. The sun gear S1 of the transmission 40 is rotated (idled) in a direction opposite to the rotation direction of the ring gear R1 in conjunction with the rotation of the ring gear R1.

  In the single motor traveling mode, the engine 10 is in a stopped state. However, since the carrier CA2 is driven by the second MG 30, the oil pump 62 operates as a mechanical oil pump.

  With reference to FIG. 6, the control state during the both motor travel mode will be described. In the both-motor running mode, the ECU 300 stops the engine 10, engages the clutch C1 of the transmission 40, and engages the brake B1. Therefore, the rotation of the sun gear S1, the carrier CA1, and the ring gear R1 of the transmission 40 is restricted.

  By restricting the rotation of the ring gear R1 of the transmission 40, the rotation of the carrier CA2 of the power distribution device 50 is also restricted (locked). In this state, ECU 300 operates first MG 20 and second MG 30 as motors. Specifically, the second MG 30 is rotated positively using the second MG torque Tm2 as a positive torque, and the first MG 20 is rotated negatively using the first MG torque Tm1 as a negative torque.

  By engaging clutch C1 and restricting rotation of carrier CA2, first MG torque Tm1 is transmitted to ring gear R2 with carrier CA2 as a fulcrum. First MG torque Tm1 (hereinafter referred to as “first MG transmission torque Tm1c”) transmitted to ring gear R2 acts in the positive direction and is transmitted to counter shaft (output shaft) 70. Therefore, in both motor travel modes, vehicle 1 travels using first MG transmission torque Tm1c and second MG torque Tm2. ECU 300 adjusts the sharing ratio between first MG torque Tm1 and second MG torque Tm2 so that the user request torque is satisfied by the sum of first MG transmission torque Tm1c and second MG torque Tm2.

  In the two-motor running mode, the rotation of the ring gear R1 and the carrier CA2 is locked, so that the oil pump 62 cannot operate as a mechanical oil pump. Therefore, the oil pump 62 operates as an electric oil pump by the motor 61 in the both-motor running mode.

  FIG. 7 is a diagram for explaining a driving mode selected in accordance with the required driving force (requested torque) and the vehicle speed from the user. In FIG. 7, the required driving force is shown on the vertical axis, and the vehicle speed is shown on the horizontal axis.

  Referring to FIG. 7, an area AR1 where the required driving force is relatively low (area surrounded by line LN10, the vertical axis, and the horizontal axis) AR1 is an area where the vehicle can travel in the single motor travel mode of the EV travel mode. An area AR2 surrounded by the line LN11 and the line LN10 is an area in which the vehicle can travel in both motor travel modes of the EV travel mode. And outside the range of area | region AR1, AR2, HV driving mode is selected.

  FIG. 8 is a collinear diagram for illustrating the shift control for suppressing cavitation according to the first embodiment.

  Referring to FIG. 8, when the vehicle is traveling forward at high gear stage Hi in the HV traveling mode, as explained in FIG. 4, clutch C1 is released and brake B1 is engaged, so that transmission 40 can be engaged. And the power distribution apparatus 50 becomes like the broken lines LN1 and LN3, respectively.

  In this state, when the rotation speed of the oil pump 62 connected to the ring gear R1 increases to the upper limit rotation speed considering the occurrence of cavitation, the clutch C1 is engaged and the brake B1 is released, so that the low gear stage. Shifted to Lo. Thereby, each rotation element S1, CA1, R1 of the transmission 40 rotates integrally (solid line LN2), and the rotational speed of the ring gear R1 decreases. At the same time, the rotational speed of the carrier CA2 of the power distribution device 50 also decreases.

  At this time, the rotation speed of the first MG 20 is adjusted so that the rotation speed of the ring gear R2, that is, the drive wheel 90 does not change (line LN4). At this time, the output torque of the second MG 30 is also adjusted as appropriate so that the output torque of the drive wheels 90 does not change.

  Thus, by shifting from the high gear stage Hi to the low gear stage Lo, the rotational speed of the oil pump 62 is reduced without changing the operating point of the engine 10 and the driving state of the drive wheels 90, and cavitation is generated. Can be suppressed.

  FIG. 9 is a functional block diagram for explaining the shift control executed by ECU 300 in the present embodiment. Each functional block described in the functional block diagram illustrated in FIG. 9 is realized by hardware or software processing by the ECU 300.

  Referring to FIG. 9, ECU 300 includes a command setting unit 310, a MOP upper limit speed setting unit 320, an MG control unit 330, an engine control unit 340, and a hydraulic pressure control unit 350.

  MOP upper limit speed setting unit 320 receives oil temperature TMP from a temperature sensor (not shown) disposed in the oil passage. The MOP upper limit speed setting unit 320 sets the upper limit rotation speed Nmax of the oil pump 62 based on the oil temperature TMP.

  The upper limit rotational speed Nmax of the oil pump 62 is set using, for example, a map as shown in FIG. Generally, it is known that cavitation tends to occur when the oil temperature TMP increases. Therefore, the upper limit rotation speed Nmax of the oil pump 62 is set so as to decrease as the oil temperature increases. The MOP upper limit speed setting unit 320 outputs the set upper limit rotation speed Nmax to the command setting unit 310.

  Command setting unit 310 includes vehicle speed VS, accelerator opening degree ACC, rotation speeds Nm1 and Nm2 of first MG 20 and second MG 30, rotation speed Ne of engine 10, state of charge (SOC) of the battery, and MOP upper limit speed setting unit. The upper limit rotational speed Nmax from 320 is received. Based on these pieces of information, command setting unit 310 sets torque command values Te, Tm1, and Tm2 for engine 10, first MG 20, and second MG 30. In addition, command setting unit 310 sets a shift command SFT for transmission 40.

  MG control unit 330 receives torque command value Tm1 of first MG 20 and torque command value Tm2 of second MG 30 from command setting unit 310. MG control unit 330 generates control signals PWI1, PWI2 for inverters 25, 35 based on these torque command values, the rotational speed of each MG, the SOC, and the like, and outputs them to inverters 25, 35.

  Engine control unit 340 generates control command DRV for engine 10 based on engine command torque Te from command setting unit 310, rotational speed Ne, and the like.

  Based on the shift command SFT from the command setting unit 310, the hydraulic control unit 350 generates engagement commands PbC and PbB for the clutch C 1 and the brake B 1 in the transmission 40 and outputs them to the hydraulic circuit 63. In addition, when the oil pump 62 is driven by the motor 61, the ECU 300 generates a control signal SE <b> 1 for driving the motor 61 and outputs it to the motor 61.

  FIG. 11 is a flowchart for illustrating details of the shift control process executed by ECU 300 in the first embodiment. The flowchart shown in FIG. 11 is realized by a program stored in advance in ECU 300 being called from a main routine and executed at a predetermined cycle. Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing.

  Referring to FIG. 11, ECU 300 determines in step (hereinafter abbreviated as “S”) 100 whether or not traveling (HV traveling mode) in which engine 10 is currently operated is being executed.

If the engine is not running (NO in S100), the subsequent processing is skipped and the processing returns to the main routine.
If the engine is running (YES in S100), the process proceeds to S110, and ECU 300 uses, for example, the map described with reference to FIG. 10 to consider the occurrence of cavitation from the oil temperature information. An upper limit rotational speed Nmax of 62 is calculated. Then, ECU 300 determines in S120 whether or not the current gear ratio is high gear stage Hi.

  If the gear ratio is high gear stage Hi (YES in S120), the process proceeds to S130, and ECU 300 determines whether rotation speed NP of oil pump 62 has reached upper limit rotation speed Nmax calculated in S110. Determine whether or not.

  When rotation speed NP reaches upper limit rotation speed Nmax (YES in S130), ECU 300 determines that cavitation may occur, and advances the process to S140. In S140, ECU 300 calculates the rotational speed of first MG 20 when the gear ratio is set to low gear stage Lo so that the operating point of engine 100 and the rotational speed of drive wheel 90 are maintained. If the first MG 20 does not over-rotate due to the calculated rotation speed, the ECU 300 shifts the gear ratio to the low gear stage Lo and adjusts the rotation speed of the first MG 20 to the rotation speed calculated in S140.

  Cavitation can occur when the gear ratio is the low gear stage Lo (NO in S120) and when the rotational speed NP of the oil pump 62 has not reached the upper limit rotational speed Nmax (No in S130). The ECU 300 advances the processing to S160, and sets the rotation speed of the engine 10, the gear ratio, and the rotation speed of the first MG 20 so that the fuel efficiency is optimized.

  By performing control according to the above-described processing, a hybrid having an oil pump that is provided with a transmission and a power distribution device between the engine and the first and second rotating electrical machines and is driven by the output shaft of the transmission In a vehicle, when the rotational speed of the oil pump is increased to a speed at which cavitation is likely to occur during traveling in the HV traveling mode, the transmission can be switched to the low speed side while maintaining the operating point of the engine. The rotational speed of the first rotating electrical machine is adjusted so that the rotational speed of the drive wheels does not fluctuate in response to a change in the rotational speed of the oil pump. Therefore, the occurrence of cavitation can be prevented while suppressing the deterioration of fuel consumption.

[Embodiment 2]
FIG. 12 is a skeleton diagram of vehicle 1A on which another drive device according to the second embodiment is mounted. In the hybrid vehicle 1A according to the second embodiment, the engine 10, the first MG 20, the second G 30, the transmission 40, and the power distribution device 50 are of a single shaft type, which is described in the first embodiment described with reference to FIG. The vehicle 1 is different. In FIG. 12, elements having the same functions as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

  Referring to FIG. 12, the drive device of vehicle 1 </ b> A is configured as a single shaft type in which engine 10, first MG 20, second G 30, transmission 40, and power distribution device 50 are arranged coaxially. Further, the drive device includes a planetary gear mechanism 55 that constitutes a speed reduction portion of the second MG 30. In the drive device according to the second embodiment, a brake B1, a first MG 20, a power distribution device 50, a clutch C1, a transmission device 40, a second MG 30, and a planetary gear mechanism 55 are arranged in this order from the side closer to the engine 10. The rotation shaft 21 of the first MG 20 and the rotation shaft 31 of the second MG 30 are hollow, and the output shaft of the engine 10, the output shaft 33 of the transmission 40, and the like are inserted therein. Such a configuration can be applied to, for example, an FR vehicle.

  As in the first embodiment, transmission 40 includes a brake B1, a clutch C1, and a planetary gear mechanism. The output shaft 11 of the engine 10 passes through the hollow rotary shaft 21 of the first MG 20 and is connected to the carrier CA1 of the planetary gear mechanism of the transmission 40. The sun gear S1 is connected to a rotation shaft provided with rotation elements of the brake B1 and the clutch C1. Ring gear R1 is coupled to carrier CA2 of power distribution device 50.

  The sun gear S2 of the power distribution device 50 is connected to the rotation shaft 21 of the first MG 20, and the ring gear R2 is connected to the output shaft 33 connected to the drive wheels. Further, a gear 64 is connected to the carrier CA2, and the rotation of the gear 64 is transmitted to the rotating shaft 65 of the oil pump 62 via the one-way clutch F1, and the oil pump 62 is driven. The oil pump 62 can also be driven by the motor 61 as in the first embodiment.

  The planetary gear mechanism 55 includes a sun gear S3, a pinion gear P3, a carrier CA3, and a ring gear R3. Sun gear S3 is connected to output shaft 31 of second MG 30. Carrier CA3 is coupled to output shaft 33 that is coupled to ring gear R2 of power distribution device 50. The ring gear R3 is fixed to a gear case (vehicle body). With such a configuration, the driving force from the second MG 30 is shifted by the planetary gear mechanism 55 and transmitted to the output shaft 33.

  Also in the drive device having such a configuration, the EV traveling mode and the HV traveling mode are set by engaging / releasing the brake B1 and the clutch C1 as described in the operation engagement table of FIG. 2 in the first embodiment. Can be switched.

  Further, since the oil pump 62 is connected to the ring gear R1 of the transmission 40 (and the carrier CA2 of the power distribution device 50), the rotational speed of the oil pump 62 varies depending on the gear ratio of the transmission 40. Therefore, even in the drive device having the configuration as shown in FIG. 12, the occurrence of cavitation can be suppressed by applying the shift control described in the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 vehicle, 10 engine, 11, 33, 67 output shaft, 20, 30 MG, 21, 31, 65 rotary shaft, 25, 35 inverter, 32 reduction gear, 40 transmission, 50 power distribution device, 51 counter drive gear, 61 motor, 62 oil pump, 63 hydraulic circuit, 64, 66 gear, 71 counter driven gear, 72 differential drive gear, 80 differential, 81 differential ring gear, 82 drive shaft, 90 drive wheel, 300 ECU, 310 command setting unit, 320 MOP upper limit speed calculation unit, 330 MG control unit, 340 engine control unit, 350 hydraulic control unit, B1 brake, C1 clutch, CA1, CA2, CA3 carrier, F1, F2 one-way clutch, P1, P2, P3 pinion gear, R1, R2, R3 ring gear, S1 , S2, S3 Sun gear.

Claims (1)

A drive device for driving a vehicle that travels using a drive force of at least one of an internal combustion engine and first and second rotating electrical machines,
A transmission coupled to the output shaft of the internal combustion engine;
A power distribution device coupled to the output shafts of the first and second rotating electrical machines and the output element of the transmission, and for transmitting the driving force from the first and second rotating electrical machines and the transmission to driving wheels. When,
An oil pump driven by the output shaft of the transmission;
A control device for controlling the first and second rotating electrical machines and the transmission,
When the rotational speed of the oil pump increases to a predetermined threshold in a travel mode in which the control device travels using the driving force from the internal combustion engine and the driving force from the second rotating electrical machine, The transmission device is controlled so that the transmission gear ratio of the transmission device becomes larger, and the rotation speed of the first rotating electrical machine is adjusted so that the rotation speed of the drive wheel is maintained when the transmission gear ratio is changed. A vehicle drive device to be adjusted.

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