JP6314819B2 - vehicle - Google Patents

Description

  The present invention relates to a vehicle, and more particularly, to a vehicle including a transmission that can selectively form a shift speed formed using a one-way clutch and a shift speed formed without using a one-way clutch.

  Japanese Patent Laying-Open No. 2013-83306 (Patent Document 1) includes a transmission and a differential device provided between an engine and two three-phase AC motor generators (a first motor generator and a second motor generator). A hybrid vehicle is disclosed. The transmission provided in the hybrid vehicle is engaged in a driving state (a state in which power is transmitted from the engine toward the driving wheel) and is driven (a state in which power is transmitted from the driving wheel toward the engine). It has a one-way clutch that is released at The transmission is configured to be able to selectively form a low speed gear stage formed using a one-way clutch and a high speed gear stage formed without using a one-way clutch.

JP 2013-83306 A

  However, in the hybrid vehicle disclosed in Patent Document 1, if the low-speed gear stage is formed and the vehicle is shifted to the driven state, the one-way clutch is idled, so that the engine brake cannot be used. Therefore, in order to use the engine brake, it is necessary to form not a low speed gear stage using a one-way clutch but a high speed gear stage not using a one-way clutch.

  However, when the low-speed gear stage is formed, the shift control is performed so as to switch to the high-speed gear stage in response to the shift to the driven state and to return to the low-speed gear stage in response to the return to the driving state. When the driving state and the driven state are frequently switched according to the acceleration / deceleration operation by the user, there is a concern that the gear stage is frequently switched and hunting of the shift control occurs.

  The present invention has been made to solve the above-described problems, and an object thereof is to make it possible to use an engine brake while preventing hunting of shift control.

  The vehicle according to the present invention is provided on the engine, the drive wheel, the power transmission path between the engine and the drive wheel, and formed using a one-way clutch, and without using the one-way clutch. A transmission capable of selectively forming the formed second shift speed, a differential provided on a power transmission path between the transmission and the drive wheel, and a control device for controlling the transmission Prepare. The control device determines whether or not a request for engine braking is expected in a driving state in which power is transmitted from the engine to the drive wheels. If it is determined that a request for engine braking is expected, the control device The transmission is controlled so as to form two shift stages.

  According to such a configuration, when it is determined that a request for engine braking is expected in the driving state, the second speed change in which the engine brake can be used in the driving state (that is, before shifting to the driven state). Steps are preformed. Therefore, even when the engine is subsequently shifted to the driven state and the engine brake is actually requested, the engine brake can be used without performing the shift control. As a result, even when the driving state and the driven state are frequently switched according to the acceleration / deceleration operation by the user, the engine brake can be used while preventing hunting of the shift control.

  Preferably, the control device determines that a request for engine braking is expected when the amount of change in the required drive torque in the drive state is a value on the acceleration side and less than a predetermined value.

  According to such a configuration, the amount of change in the required driving force in the driving state is a value on the acceleration side and less than a predetermined value (for example, a value corresponding to “threshold value Tsh” in S10 of FIG. 9). In this case, in view of the fact that it is easy to subsequently shift to the driven state, it is possible to form in advance a second gear that can use the engine brake in the driven state.

  Preferably, the vehicle further includes a motor generator connected to the drive wheels and a power storage device that receives the regenerative power of the motor generator. The control device determines that an engine brake request is expected when the amount of power stored in the power storage device is equal to or greater than a predetermined value in the drive state.

  According to such a configuration, when the storage amount of the power storage device that receives the regenerative power of the motor generator is equal to or greater than a predetermined value (for example, a value corresponding to “threshold value S1” in S11 of FIG. 9), In view of the fact that the regenerative braking of the motor generator is limited and the demand for engine braking is expected when the state is shifted to the driven state, it is necessary to form in advance in the second gear stage that can use the engine brake in the driving state. it can.

  Preferably, when it is not determined that a request for engine braking is expected in the driving state, the control device determines which of the first gear and the second gear is to be formed in the transmission based on the vehicle speed and the required driving torque. decide.

  According to such a configuration, when it is not determined that a request for engine braking is expected in the driving state, an optimal shift speed corresponding to the vehicle speed and the required drive torque is selected from the first shift speed and the second shift speed. can do.

It is a figure which shows the whole structure of a vehicle. It is the block diagram which showed the structure of the control apparatus. It is a figure which shows the action | operation engagement table | surface of the one-way clutch F1 and brake B1 of a transmission. FIG. 7 is a nomographic chart in the HV traveling mode (low gear stage Lo). It is a collinear diagram in HV driving mode (high gear stage Hi). It is an alignment chart in the single motor travel mode. It is a collinear diagram in both motor drive modes. It is the figure which illustrated the correspondence of vehicle speed, demanded driving force, and run mode. It is a flowchart which shows the process sequence which a control apparatus performs. It is the figure which showed an example of the operating point control of a differential apparatus on the alignment chart. It is a figure which shows an example of a state change in the case of shifting to the high gear stage Hi from the low gear stage Lo in the driving state in the HV traveling mode. It is the figure which showed an example of the shift map.

  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.

[Overall configuration of hybrid vehicle]
FIG. 1 is a diagram illustrating an overall configuration of a vehicle 1 including a drive device according to the present embodiment. 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, and inverters for driving the first MG 20 and the second MG 30, respectively. 25, 35, a transmission 40, a differential gear (planetary gear device) 50, a counter shaft (output shaft) 70, a differential gear 80, drive wheels 90, and a control device 100.

  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 engine 10 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine. The engine 10 is controlled by a control signal from the control device 100.

  First MG 20 and second MG 30 are, for example, permanent magnet type three-phase (U-phase, V-phase, W-phase) AC rotating electrical machines 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. Inverters 25 and 35 convert DC power from a driving battery (not shown) into AC power in accordance with a control signal from control device 100 and supply the AC power to first MG 20 and second MG 30, respectively. Inverters 25 and 35 convert AC power generated by first MG 20 and second MG 30 into DC power in accordance with a control signal from control device 100 and supplies the DC power to the driving battery.

  Second MG 30 can generate a braking force (regenerative brake) by generating electric power. The regenerative power generated by the second MG 30 is received by the drive battery.

  The transmission device 40 is provided on a power transmission path between the engine 10 and the differential device 50, changes the rotation of the engine 10, and outputs it to the differential 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 one-way clutch F1, 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, as will be described later, are related by a straight line on the nomograph (that is, any two rotations). If the speed is determined, the remaining rotational speed is also determined).

  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 one-way clutch F1 is provided between the sun gear S1 and the carrier CA1, and allows relative rotation in the positive direction of the carrier CA1 with respect to the sun gear S1, and suppresses relative rotation in the negative direction.

  Specifically, when the carrier CA1 tries to rotate in the forward direction relative to the sun gear S1, the one-way clutch F1 is released and idles. As a result, the sun gear S1 and the carrier CA1 are separated from each other, so that the carrier CA1 is rotated relative to the sun gear S1 in the positive direction (the rotation speed of the carrier CA1 is higher than the rotation speed of the sun gear S1). Is done.

  On the other hand, when the carrier CA1 tries to rotate in the negative direction relative to the sun gear S1, the one-way clutch F1 is engaged. Thereby, since sun gear S1 and carrier CA1 rotate integrally, relative rotation of carrier CA1 in the negative direction with respect to sun gear S1 (the rotation speed of carrier CA1 becomes higher than the rotation speed of sun gear S1) is suppressed. The

  Therefore, in a state where the rotation speed of carrier CA1 is higher than the rotation speed of sun gear S1, one-way clutch F1 is released. On the other hand, when the rotational speed of the sun gear S1 reaches the rotational speed of the carrier CA1, the one-way clutch F1 is engaged.

  The transmission 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 a one-way clutch. It is switched according to the combination of engagement and release of F1 and brake B1.

  When the brake B1 is released, the rotation of the sun gear S1 is not restricted. Therefore, in a driving state (a state in which power is transmitted from the engine 10 to the driving wheels 90), the rotational speed of the sun gear S1 is increased to the rotational speed of the carrier CA1 by the output torque of the engine 10, and the one-way clutch F1 is engaged. Combined. As a result, a low gear stage Lo having a gear ratio of 1.0 (directly connected state) is formed. On the other hand, in a driven state (a state in which power is transmitted from the drive wheels 90 to the engine 10), the rotational speed of the ring gear R1 is increased by the positive torque input from the drive wheels 90 to the ring gear R1, and the ring gear is increased. Due to the rise in the rotation of R1, the rotational speed of the sun gear S1 decreases with the carrier CA1 as a fulcrum by the lever principle. As a result, the rotational speed of the sun gear S1 is relatively lower than the rotational speed of the carrier CA1, so that the one-way clutch F1 is released. As a result, when the low gear stage Lo is selected (the state where the brake B1 is released), the power from the drive wheels 90 cannot be transmitted to the engine 10 in the driven state, and so-called engine braking is applied. I can't let you.

  On the other hand, in a state where the brake B1 is engaged, the rotation of the sun gear S1 is restricted, so that the rotation speed of the carrier CA1 is relatively higher than the rotation speed of the sun gear S1, and the one-way clutch F1 is released. As a result, a high gear stage Hi is formed in which the gear ratio is a value smaller than 1.0 (for example, 0.7, so-called overdrive state). That is, the high gear stage Hi is formed using the brake B1 instead of the one-way clutch F1. Since the brake B1 can be engaged even in the driven state, the engine brake can be applied during the formation of the high gear stage Hi.

  The differential 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 differential device 50 is connected to a 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 differential device 50 that rotates integrally with the ring gear R2.

  As described later, 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 are connected in a straight line on the nomograph (that is, any two rotations). If the speed is determined, the remaining rotational 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 driven gear 71 and a drive gear 72. The driven gear 71 meshes with the counter drive gear 51 of the differential device 50. 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 differential device 50.

  The transmission device 40 and the differential 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 differential device 50.

  The driven gear 71 also meshes with the reduction gear 32 connected to the rotation shaft 31 of the 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 drive gear 72 meshes with the diff ring gear 81 of the differential gear 80. The differential gear 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 gear 80.

  The vehicle 1 includes an electric oil pump (hereinafter also referred to as “EOP”) 61, a mechanical oil pump (hereinafter also referred to as “MOP”) 62, and a hydraulic circuit 63 as a configuration for supplying hydraulic pressure to the transmission 40. . The EOP 61 is driven by a motor (hereinafter also referred to as “internal motor”) provided therein, generates hydraulic pressure, and supplies it to the hydraulic circuit 63. The internal motor of the EOP 61 is controlled by a control signal from the control device 100. The MOP 62 is connected to the carrier CA2 of the differential device 50 and is operated by the power transmitted from the carrier CA2 to generate hydraulic pressure. Therefore, when the carrier CA2 is rotated, the MOP 62 is also operated, and when the carrier CA2 is stopped, the MOP 62 is also stopped.

  The hydraulic circuit 63 includes a solenoid valve that regulates the hydraulic pressure supplied to the brake B1 of the transmission 40 (hereinafter also referred to as “B1 hydraulic pressure”) using the hydraulic pressure supplied from at least one of the EOP 61 and the MOP 62 as a source pressure. The solenoid valve is controlled by a control signal from the control device 100.

[Configuration of control device]
FIG. 2 is a block diagram showing the configuration of the control device 100 in FIG. Control device 100 includes an HVECU (Electric Control Unit) 150, MGECU 160, and engine ECU 170. Each of HVECU 150, MGECU 160, and engine ECU 170 is an electronic control unit including a computer. Note that the number of ECUs is not limited to three, and may be integrated into one ECU as a whole, or may be divided into two or four or more numbers.

  The MGECU 160 controls the first MG 20 and the second MG 30. For example, the MGECU 160 controls the output torque of the first MG 20 by adjusting the current value supplied to the first MG 20, and controls the output torque of the second MG 30 by adjusting the current value supplied to the second MG 30. .

  The engine ECU 170 controls the engine 10. The engine ECU 170 performs, for example, control of the opening degree of the electronic throttle valve of the engine 10, engine ignition control by outputting an ignition signal, fuel injection control to the engine 10, and the like. The engine ECU 170 controls the output torque of the engine 10 by electronic throttle valve opening control, injection control, ignition control, and the like.

  The HVECU 150 performs integrated control of the entire vehicle. A vehicle speed sensor, an accelerator opening sensor, an MG1 rotation speed sensor, an MG2 rotation speed sensor, an output shaft rotation speed sensor, a battery sensor, and the like are connected to the HVECU 150. With these sensors, the HVECU 150 causes the vehicle speed, the accelerator opening, the rotational speed (rotational speed) of the first MG 20, the rotational speed (rotational speed) of the second MG 30, the rotational speed (rotational speed) of the output shaft of the power transmission device, for driving The battery's SOC (State Of Charge) or the like is acquired.

  Further, the shift range from the shift sensor that detects the shift lever operation by the user is input to the HVECU 150. The shift range includes a parking (P) range, a reverse (R) range, a neutral (N) range, a forward (D) range, and a brake (B) range. In the B range, the target deceleration (target braking force) when the accelerator opening is 0 is set to a value larger than that in the D range. Therefore, the user can request a larger deceleration (braking force) on a downhill or the like by selecting the B range.

  Further, the operation mode from the mode select switch is input to HVECU 150. The driving mode includes a sports mode and a normal (non-sport) mode. In the sport mode, the target acceleration and the target deceleration for the same accelerator opening are set to values larger than those in the normal mode. Thus, the user can request greater acceleration and deceleration by selecting a sport mode.

  The HVECU 150 calculates a required driving force, a required driving torque, and the like for the vehicle based on the acquired information. Based on the calculated required value, HVECU 150 outputs torque of first MG 20 (hereinafter also referred to as “MG1 torque”), output torque of second MG 30 (hereinafter also referred to as “MG2 torque”), and engine 10. The output torque (hereinafter also referred to as “engine torque”) is determined. HVECU 150 outputs a command value for MG1 torque and a command value for MG2 torque to MGECU 160. Further, HVECU 150 outputs an engine torque command value to engine ECU 170.

  The HVECU 150 controls the brake B1 of the transmission 40 according to a travel mode described later. The HVECU 150 outputs the B1 oil pressure command value PbB1 to the solenoid valve of the hydraulic circuit 63 in FIG.

[Driving mode of vehicle 1]
The control device 100 causes the vehicle 1 to travel in a hybrid travel mode (hereinafter referred to as “HV travel mode”) or a motor travel mode (hereinafter referred to as “EV travel mode”). The HV travel mode is a travel 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 travel 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.

  The EV travel mode is further subdivided into a single motor travel mode and a dual motor travel mode. The single motor travel mode is a travel mode in which the vehicle 1 travels with the power of the second MG 30 alone. The both motor travel mode is a travel mode in which the vehicle 1 travels with the power of both the first MG 20 and the second MG 30.

  FIG. 3 is a diagram showing an operation engagement table of the one-way clutch F1 and the brake B1 of the transmission 40 in each travel mode. In FIG. 2, “F1”, “B1”, “MG1”, and “MG2” indicate the one-way clutch F1, the brake B1, the first MG20, and the second MG30, respectively. The circle (◯) in the C1 and B1 columns indicates “engaged”, the x indicates “released”, the triangle (Δ) indicates “engaged” in the driven state, and “released” in the driven state. ". Further, “G” in the MG1 column and MG2 column indicates that the operation is mainly performed as a generator, and “M” indicates that the operation is mainly performed as a motor.

  In the HV traveling mode, the control device 100 switches the gear ratio of the transmission 40 according to the vehicle speed. When the vehicle 1 is moved forward in the middle / low speed range or when the vehicle 1 is moved backward, the control device 100 releases the brake B1. As a result, the one-way clutch F1 is engaged in the driving state to form the low gear stage Lo (see FIG. 4 described later). On the other hand, when the vehicle 1 is advanced in the high speed range, the control device 100 engages the brake B1. As a result, the one-way clutch F1 is released and a high gear stage Hi is formed (see FIG. 5 described later). Further, in the HV traveling mode, control device 100 operates first MG 20 mainly as a generator, and operates second MG 20 mainly as a motor.

  In the EV travel mode, the control device 100 selectively switches between the single motor travel mode and the both motor travel mode described above.

  When a driving force (a force for moving forward or backward) is applied to the vehicle 1 in the single motor traveling mode, the control device 100 releases the brake B1. As a result, the one-way clutch F1 is released and the transmission 40 is in a neutral state (a state in which power is not transmitted). On the other hand, when the engine brake is applied to the vehicle 1 in the single motor travel mode, the control device 100 engages 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, control device 100 operates first MG 20 mainly as a generator and second MG 20 mainly as a motor (see FIG. 6 described later).

  When the vehicle 1 travels (forwards or reverses) in the both motor travel mode, the control device 100 engages the brake B1 and engages the one-way clutch F1 by applying the torque of the first MG 20 in the negative direction. As a result, the rotational speeds of the rotation elements S1, CA1, R1 of the transmission 40 and the carrier CA2 of the differential device 50 are fixed to zero. In the both-motor running mode, control device 100 operates first MG 20 and second MG 20 mainly as motors (see FIG. 7 described later).

  4 to 7 are alignment charts during the HV traveling mode (low gear stage Lo), during the HV traveling mode (high gear stage Hi), during the single motor traveling mode, and during both motor traveling modes, respectively. 4 to 7, “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” indicate differential devices, respectively. 50 sun gear S2, carrier CA2, and ring gear R2 are shown.

  With reference to FIG. 4, the control state in the case of traveling forward at the low gear stage Lo during the HV traveling mode will be described. When the low gear stage Lo is formed, the one-way clutch F1 is engaged and the brake B1 is released, so that the rotation elements S1, CA1, R1 of the transmission 40 rotate together. Thereby, the rotation of the engine 10 input to the carrier CA1 of the transmission 40 is transmitted from the ring gear R1 to the carrier CA2 of the differential 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 differential device 50. The torque output from the ring gear R1 (hereinafter referred to as “transmission part output torque Tr1”) is the same as the engine torque Te (Te = Tr1) when the low gear stage Lo is formed.

  The rotation of the engine 10 transmitted to the carrier CA2 of the differential device 50 is steplessly changed by the rotational speed of the sun gear S2 (rotational speed of the first MG 20) and transmitted to the ring gear R2 of the differential device 50. At this time, control device 100 causes the torque of first MG 20 (hereinafter also referred to as “first MG torque Tm1”) to act in the negative direction. Thereby, the first MG torque Tm1 acts as a reaction torque 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, the torque of the second MG 30 (hereinafter also 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. Therefore, in the HV traveling mode, the vehicle 1 travels using the engine transmission torque Tec and the second MG torque Tm2.

  Next, with reference to FIG. 5, the control state when the vehicle is traveling forward at the high gear stage Hi during the HV traveling mode will be described. Since the brake B1 is engaged when the high gear stage Hi is formed, the rotation of the sun gear S1 is restricted. As a result, the rotational speed of the carrier CA1 is relatively higher than the rotational speed of the sun gear S1, and the one-way clutch F1 is released. As a result, 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 differential device 50. Therefore, the transmission output torque Tr1 is smaller than the engine torque Te (Te> Tr1).

  Next, with reference to FIG. 6, the control state in the case of traveling forward during the single motor traveling mode will be described. In the single motor travel mode, control device 100 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, control device 100 feedback-controls first MG torque Tm1 so that the rotational speed of sun gear S2 becomes zero. Therefore, the sun gear S2 does not rotate. On the other hand, since the one-way clutch F1 and the brake B1 of the transmission 40 are released, the rotation of the carrier CA2 of the differential device 50 is not restricted. Therefore, ring gear R2 of differential 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.

  Next, with reference to FIG. 7, the control state in the case of traveling forward during the both-motor traveling mode will be described. In the both-motor running mode, the engine 10 is stopped, the one-way clutch F1 of the transmission 40 is engaged, and the brake B1 is engaged. Thereby, rotation of rotation element S1, CA1, R1 of the transmission 40 is controlled. By restricting the rotation of the ring gear R1 of the transmission 40, the rotation of the carrier CA2 of the differential device 50 is also restricted.

  In a state where the rotation of carrier CA2 is restricted, control device 100 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. First MG torque Tm1 is transmitted to ring gear R2 using 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.

  Control device 100 adjusts the torque sharing ratio between first MG torque Tm1 and second MG torque Tm2 with respect to the required drive torque so that the required torque is satisfied by the sum of first MG transmission torque Tm1c and second MG torque Tm2.

[Switch driving mode]
When the SOC of the drive battery is lower than the threshold value, the control device 100 operates the engine 10 to charge the drive battery and causes the vehicle 1 to travel in the HV travel mode. On the other hand, when the SOC of the driving battery is higher than the threshold value, control device 100 switches the traveling mode of vehicle 1 based on the vehicle speed and the required driving force.

  FIG. 8 is a diagram illustrating a correspondence relationship between the vehicle speed, the required driving force, and the traveling mode when the SOC of the driving battery is higher than the threshold value. In FIG. 8, the boundary line L <b> 1 corresponds to the output possible driving force of the second MG, and the boundary line L <b> 2 corresponds to the sum of the output possible driving force of the first MG 20 and the output possible driving force of the second MG 30.

  In the region below the boundary line L1, the required driving force can be output by the second MG 30 alone. Therefore, the control device 100 causes the vehicle 1 to travel in the single motor travel mode.

  In the region exceeding the boundary line L1 and less than the boundary line L2, the second MG 30 alone cannot output the required driving force, but the first MG 20 and the second MG 30 can output the required driving force. Causes the vehicle 1 to travel in both motor travel modes.

  In the region exceeding the boundary line L2, the required driving force cannot be output by both the first MG 20 and the second MG 30, so the control device 100 causes the vehicle 1 to travel in the HV traveling mode.

[Gear stage selection in driving state in HV traveling mode]
In the vehicle 1 having the above-described configuration, when the one-way clutch F1 is engaged and the low gear stage Lo is formed in the HV traveling mode, the one-way clutch F1 is released when the driving state is shifted to the driven state. The engine brake cannot be used because the engine is idle and idles. Therefore, in order to use the engine brake, it is necessary to form a high gear stage Hi that does not use the one-way clutch F1, instead of the low gear stage Lo that uses the one-way clutch F1.

  However, when the low gear stage Lo is formed, the shift control is performed such that the high gear stage Hi is switched according to the driven state and the low gear stage Lo is returned again when the driving state is restored. When the driven state and the driving state are frequently switched according to the acceleration / deceleration operation by the user, there is a concern that the gear stage is frequently switched and the shift control is hunted.

  Therefore, the control device 100 according to the present embodiment determines whether or not a request for engine braking is expected in the driving state in the HV traveling mode, and if it is determined that a request for engine braking is expected, the driving is performed. In the state (that is, before shifting to the driven state), the transmission 40 is controlled to preliminarily form a high gear stage Hi that can use the engine brake. Hereinafter, this point will be described in detail.

  FIG. 9 is a flowchart showing a processing procedure performed by control device 100 in the driving state in the HV traveling mode.

  In the processing of steps (hereinafter abbreviated as “S”) 10 to S12, the control device 100 determines whether or not a request for engine braking is expected.

  Specifically, in S10, control device 100 determines whether or not the amount of change in required drive torque is greater than 0 (acceleration side value) and lower than threshold value Tsh. This determination determines whether or not the change amount of the required drive torque is a value on the acceleration side (a value larger than 0), but the user has little intention of acceleration and is easily shifted to the driven state. It is. Therefore, the threshold value Tsh is preset to a value slightly larger than zero.

  In S11, control device 100 determines whether or not the SOC of the drive battery is larger than threshold value S1. This determination is made as to whether or not the regenerative braking by the second MG 30 is limited because the SOC of the driving battery is high and the regenerative power by the second MG 30 cannot be sufficiently received when the state is shifted to the driven state. It is a process to do. Therefore, threshold value S1 is set to a value close to the SOC control upper limit value.

  In S12, control device 100 determines whether or not the shift range is the B range. This determination is a process for determining whether or not the target braking force is greater than the regenerative braking by the second MG 30 if the B range is selected and the state is shifted to the driven state. .

  When change amount of required drive torque is lower than threshold value Tsh and SOC of drive battery is higher than threshold value S1 (YES in S10 and YES in S11), or the change amount of required drive torque is If lower than threshold value Tsh and the shift range is B range (YES in S10 and YES in S12), control device 100 determines that a request for engine braking is expected.

  On the other hand, if the amount of change in required drive torque is higher than threshold value Tsh (NO in S10), or if the SOC of the drive battery is lower than threshold value S1 and the shift range is not the B range (in S11) If YES and YES in S12), control device 100 does not determine that a request for engine braking is expected.

  When it is determined that an engine brake request is expected (YES in S10 and YES in S11, or YES in S10 and YES in S12), control device 100 requests future engine brake in S13. In preparation for this, the high gear stage Hi is formed in advance in the driving state (that is, before shifting to the driven state). That is, the control device 100 performs the upshift to the high gear stage Hi when the low gear stage Lo is formed, and maintains the high gear stage Hi as it is when the high gear stage Hi is already formed. As a result, the low gear stage Lo that cannot use the engine brake cannot be used.

  In response to the formation of the high gear stage Hi in S13, the control device 100 executes the operating point control of the differential device 50 in S14.

  FIG. 10 shows an example of the operating point control of the differential device 50 when shifting from the low gear stage Lo to the high gear stage Hi without changing the operating point (rotational speed and torque) of the engine 10. FIG.

  When the vehicle is traveling forward at the low gear stage Lo in the HV traveling mode, as described with reference to FIG. 4 above, the one-way clutch F1 is engaged and the brake B1 is released, so that each rotational element of the transmission 40 is S1, CA1, and R1 rotate together (line LN1). At this time, in the differential device 50, for example, a state like a line LN3 is set depending on the operation state of the first MG 20 and the second MG 30.

  When the brake B1 is engaged and the gear is shifted to the high gear stage Hi from this low gear stage Lo state, the sun gear S1 is fixed and the sun gear S1 has a rotational speed of 0, so that the rotational speed of the ring gear R1 is about the engine 10 as a fulcrum. Ascend to a state as indicated by line LN2.

  At this time, control device 100 adjusts first MG torque Tm1 to increase the rotational speed of sun gear S2. This control is the operating point control of the differential device 50 (control of S14 in FIG. 10). During the speed change, the vehicle speed does not substantially change and the rotation speed of the ring gear R2 is constant. Therefore, by increasing the rotation speed of the sun gear S2 by operating point control of the differential apparatus 50, the rotation speed of the carrier CA2 of the differential apparatus 50 is increased. Can also be raised (line LN4). Accordingly, the rotational speed of the carrier CA2 of the differential device 50 can be increased according to the increase in the rotation of the ring gear R1 of the transmission 40. As a result, the speed ratio of the differential device 50 (ratio between the rotational speed of the carrier CA2 and the rotational speed of the ring gear R2) is quickly controlled to a value suitable for the high gear stage Hi after the speed change.

  FIG. 11 is a diagram illustrating an example of a state change when shifting from the low gear stage Lo to the high gear stage Hi without changing the operating point of the engine 10 in the driving state in the HV traveling mode. The time is shown on the horizontal axis of FIG. 11, and the rotation speed of the engine 10, the torque of the first MG 20, the rotation speed of the first MG 20, the torque of the second MG 30, the rotation speed of the second MG 30, the B1 hydraulic pressure, The rotational speed of the carrier CA2 and the SOC of the driving battery are shown.

  In the example shown in FIG. 11, it is determined that a request for engine braking is expected in response to the SOC of the driving battery rising above the threshold value S1 at time t1. Along with this determination, at time t2, the B1 hydraulic pressure starts to increase, and the shift from the low gear stage Lo to the high gear stage Hi is started.

  When the inertia phase starts at time t <b> 3, control device 100 increases the rotation speed of first MG 20 by adjusting the torque of first MG 20.

  When the B1 hydraulic pressure rises to a predetermined engagement pressure at time t4 and the engagement of the brake B1 is completed, the shift to the high gear stage Hi is completed. After the formation of the high gear stage Hi, the engine brake can be used in the driven state.

  Returning to FIG. 9, if it is not determined that a request for engine braking is expected (NO in S10 or NO in S12), control device 100 determines in S15 the vehicle speed and high gear stage Hi and low gear stage Lo. A gear stage corresponding to the required drive torque is selected based on the shift diagram. As a result, the use of the low gear stage Lo is permitted.

  FIG. 12 is a diagram showing an example of a shift map used for selecting the gear stage (the process of S15 in FIG. 9). In FIG. 12, the horizontal axis represents the vehicle speed, and the vertical axis represents the required drive torque. The maximum torque line Tmax corresponds to the driving torque that can be output by the vehicle 1.

  The Lo fixed region shown in FIG. 12 is a region exceeding the boundary torque line T1 and less than the maximum torque line Tmax. In the Lo fixed region, when the high gear stage Hi is selected, the driving torque is insufficient, so the selected gear stage is fixed to the low gear stage Lo.

  The Hi / Lo selection region shown in FIG. 12 is a region below the boundary torque line T1. In the Hi / Lo selection region, either the high gear stage Hi or the low gear stage Lo is selected according to the vehicle speed and the required drive torque. In the example shown in FIG. 12, the low gear stage Lo is selected when the intersection of the vehicle speed and the required driving torque exceeds the boundary torque line T2 so that the optimum fuel consumption is obtained, and the intersection of the vehicle speed and the required driving torque is the boundary. When it is less than the torque line T2, the high gear stage Hi is selected.

  In the process of S15 in FIG. 9, when a shift (switching between the low gear stage Lo and the high gear stage Hi) is performed, the control device 100 controls the operating point of the differential device 50 in the same manner as S14 in FIG. To do.

  As described above, control device 100 according to the present embodiment determines whether or not a request for engine brake is expected in the driving state in the HV traveling mode, and when it is determined that a request for engine brake is expected. Pre-forms a high gear stage Hi that can use the engine brake in the drive state. Therefore, even when the engine is subsequently shifted to the driven state and the engine brake is actually requested, the engine brake can be used without performing the shift control. As a result, even when the driving state and the driven state are frequently switched according to the acceleration / deceleration operation by the user, the engine brake can be used while preventing hunting of the shift control.

<Modification>
The above-described embodiment can be modified as follows, for example.

  (1) In the above-described embodiment, the case where the “threshold value Tsh” compared with the change amount of the required drive torque in S10 of FIG. 9 is set to a fixed value slightly larger than 0 has been described. The “threshold value Tsh” may be a value that varies according to the vehicle speed or the like.

  For example, the “threshold value Tsh” may be a value that varies as the vehicle speed increases. If it does in this way, it can be determined appropriately according to a vehicle speed whether it is easy to shift to a driven state (whether the demand of engine brake is anticipated).

Further, it is determined whether or not an engine brake request is expected only in a region (Hi / Lo selection region shown in FIG. 12) in which the low gear stage Lo and the high gear stage Hi shown in the shift diagram of FIG. 12 can be selected. May be.
(2) In the above-described embodiment, the case where it is determined whether or not the shift range is the B range in S12 of FIG. 9 has been described, but instead of or in addition to the determination of the B range in S12 of FIG. It may be determined whether or not the sport mode is selected.

In this case, when the sport mode is selected, the target braking force is set to a larger value than when the normal mode is selected and the engine brake request is expected when the state is shifted to the driven state. Can be determined.
(3) In the above-described embodiment, the example in which the high gear stage Hi is fixed in S13 when both the conditions of S10 and S11 in FIG. 9 are satisfied has been described. If established, the high gear stage Hi may be fixed in S13.

  Further, the above-described embodiment and its modification examples can be combined as appropriate.

  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, 20 1st MG, 30 2nd MG, 25, 35 inverter, 32 reduction gear, 40 transmission, 50 differential, 51 counter drive gear, 63 hydraulic circuit, 71 driven gear, 72 drive gear, 80 differential Gear, 81 diff ring gear, 82 drive shaft, 90 drive wheel, 100 controller, B1 brake, CA1, CA2 carrier, F1 one-way clutch, P1, P2 pinion gear, R1, R2 ring gear, S1, S2 sun gear.

Claims (4)

Engine,
Driving wheels,
A first shift stage provided on a power transmission path between the engine and the drive wheel and formed using a one-way clutch, and a second shift stage formed without using a one-way clutch are selectively used. A formable transmission,
A differential provided on a power transmission path between the transmission and the drive wheel, the carrier connected to the transmission, a sun gear, and a ring gear connected to the drive wheel ;
A first motor generator connected to the sun gear of the differential;
A second motor generator connected to the drive wheel;
A power storage device that receives the regenerative power of the second motor generator;
A control device for controlling the transmission,
The controller determines whether or not a request for engine brake is expected in a driving state in which power is transmitted from the engine toward the drive wheel, and when it is determined that a request for engine brake is expected, Controlling the transmission to form the second shift stage in the driving state ;
The control device determines that a request for the engine brake is expected when the power storage amount of the power storage device is equal to or greater than a predetermined value in the driving state;
When the shift from the first shift stage to the second shift stage is performed when it is determined that the demand for the engine brake is expected in the driving state, the control device may The vehicle controls the first motor generator so as not to change the operating point of the engine .   2. The control device according to claim 1, wherein the control device determines that a request for the engine brake is expected when a change amount of the required drive torque is a value on an acceleration side and less than a predetermined value in the drive state. vehicle. The transmission includes a planetary gear device including a carrier connected to the engine, a sun gear, and a ring gear connected to the differential device; a brake element that restricts rotation of the sun gear of the planetary gear device; Including the one-way clutch,
The vehicle according to claim 1, wherein the one-way clutch allows relative rotation in one direction of the carrier of the transmission with respect to a sun gear of the transmission and suppresses relative rotation in the other direction.   When it is not determined that the demand for the engine brake is expected in the driving state, the control device determines which of the first gear and the second gear is to be formed in the transmission. The vehicle according to claim 1, wherein the vehicle is determined based on

Images