JP2022175914A - vehicle - Google Patents

Abstract

To prevent the direction of drive torque of a drive wheel from being reversed when a plurality of drive wheels are driven in a configuration in which the plurality of drive wheels are connected to a power source via a differential gear.SOLUTION: A vehicle includes: a first rotary electric machine, a second rotary electric machine, a differential device having three rotary elements; and a control device that controls the first rotary electric machine and the second rotary electric machine. When the control device executes dual drive control for driving the first rotary electric machine and the second rotary electric machine, the vehicle drives a first drive wheel and a second drive wheel while positive torque from the first rotary electric machine and negative torque from the second rotary electric machine act on a third rotary element. When executing dual drive control, the control device executes control so that drive torque of the first drive wheel becomes positive toque.SELECTED DRAWING: Figure 4

Description

The present invention relates to vehicles.

In Patent Document 1, in a vehicle provided with a first motor that is a power source for front wheels and a second motor that is a power source for rear wheels, the power consumption of the first motor and the power consumption of the second motor are different. It is disclosed that four-wheel drive is performed by a combination of motor torques that minimizes the sum of .

JP 2006-180657 A

As a power transmission device mounted on a vehicle, a transfer that distributes power output from a main power source (first power source) to front wheels and rear wheels is known. The transfer comprises a differential, the output of which is connected to the front propeller shaft and the rear propeller shaft. The transfer switches between a two-wheel drive state, which outputs power to only one propeller shaft, and a four-wheel drive state, which outputs power to both propeller shafts. Further, when the vehicle is provided with a secondary power source (second power source), the secondary power source is connected to the differential, so that the magnitude of the torque distributed to the front wheels and the rear wheels is controlled by the secondary power source. can be controlled by the power of

However, in this vehicle, when four-wheel drive is performed with the differential operating, the direction of the torque acting on each propeller shaft from the auxiliary power source is reversed. That is, when traveling using the main power source and the secondary power source, negative torque from the secondary power source acts on one of the propeller shafts. It must act on the propeller shaft. However, when the control described in Patent Document 1 is applied to this vehicle, the negative torque acting on one of the propeller shafts cannot be canceled, and the direction of the drive torque for the front wheels and the direction of the drive torque for the rear wheels are different. There is a risk that it will turn in the opposite direction and you will not be able to drive.

The present invention has been made in view of the above circumstances. To provide a vehicle capable of preventing the direction of a vehicle from being reversed.

In the present invention, a first rotating electric machine, a second rotating electric machine, a first output shaft connected to a first drive wheel, a second output shaft connected to a second drive wheel, and three rotating elements, a first rotating element to which the second rotating electric machine is connected, a second rotating element to which the second output shaft is connected, and a third rotating element to which the first rotating electric machine and the first output shaft are connected; and a control device for controlling the first rotating electrical machine and the second rotating electrical machine, wherein the control device drives both the first rotating electrical machine and the second rotating electrical machine. When executing drive control, the first driving wheel and the second driving wheel are operated in a state in which positive torque from the first rotating electric machine and negative torque from the second rotating electric machine act on the third rotating element. wherein the control device performs control so that the drive torque of the first drive wheel becomes positive torque when executing the dual drive control.

According to this configuration, when driving the first driving wheel and the second driving wheel, even if negative torque from the second rotating electric machine acts on the third rotating element, the driving torque of the first driving wheel can be controlled to a positive torque. As a result, the direction of the drive torque of the first drive wheel and the direction of the drive torque of the second drive wheel can be prevented from being opposite to each other.

Further, the control device controls the power of the first rotating electric machine and the power of the first rotating electric machine so that the positive torque acting on the third rotating element from the first rotating electric machine becomes larger than the negative torque during execution of the dual drive control. The power of the second rotating electric machine may be controlled.

According to this configuration, when the first driving wheel and the second driving wheel are driven, the positive torque acting on the third rotating element from the first rotating electrical machine becomes the negative torque acting on the third rotating element from the second rotating electrical machine. By being larger than the torque, the drive torque of the first drive wheel can be made positive torque.

In addition, during execution of the dual drive control, the control device controls the first rotating electric machine within a range in which the positive torque acting on the third rotating element from the first rotating electric machine can be maintained larger than the negative torque. may be reduced, and the power of the second rotating electric machine may be increased.

According to this configuration, it is possible to suppress the power of the first rotating electric machine while increasing the power of the second rotating electric machine in a state where the direction of the driving torque is not reversed between the first driving wheel and the second driving wheel. can.

In addition, during execution of the dual drive control, the control device controls the second rotating electric machine within a range in which the positive torque acting on the third rotating element from the first rotating electric machine can be maintained larger than the negative torque. may be larger than the power of the first rotating electric machine.

According to this configuration, the motive power of the second rotating electric machine can be made larger than the motive power of the first rotating electric machine in a state in which the directions of the driving torques of the first driving wheel and the second driving wheel are not opposite to each other. As a result, in terms of the efficiency of the power transmission device, when the power of the second rotating electric machine can be transmitted more efficiently than the power of the first rotating electric machine, the power of the first rotating electric machine is suppressed, thereby improving fuel efficiency. can be made

Further, when starting the vehicle, the control device may execute start control to drive the second rotating electrical machine after driving the first rotating electrical machine.

According to this configuration, it is possible to start driving the second rotating electric machine in a state where the positive torque from the first rotating electric machine is acting on the third rotating element. As a result, it is possible to prevent the torque of the third rotating element from becoming negative torque.

Further, the control device controls the control device so that, during execution of the start control, after the second rotating electric machine is driven, the positive torque acting from the first rotating electric machine on the third rotating element becomes larger than the negative torque. Power of the first rotating electrical machine and power of the second rotating electrical machine may be controlled.

According to this configuration, when the vehicle starts moving, the positive torque acting on the third rotating element from the first rotating electrical machine is greater than the negative torque acting on the third rotating element from the second rotating electrical machine. The drive torque of the drive wheels can be positive torque.

In the present invention, when driving the first drive wheel and the second drive wheel, even if negative torque from the second rotating electric machine acts on the third rotating element, the drive torque of the first drive wheel is positive. Torque can be controlled. As a result, the direction of the drive torque of the first drive wheel and the direction of the drive torque of the second drive wheel can be prevented from being opposite to each other.

FIG. 1 is a skeleton diagram that schematically shows the vehicle of the embodiment. FIG. 2 is a collinear diagram showing the state of the rotating elements of the differential gear in the four-wheel drive state. FIG. 3 is a diagram showing the relationship between the front propeller torque and the rear propeller torque. FIG. 4 is a diagram for explaining a state in which the rear propeller torque becomes positive torque. FIG. 5 is a diagram showing the relationship between the first motor torque and the second motor torque when the rear propeller torque is positive torque. FIG. 6 is a time chart diagram for explaining a case where the vehicle of the embodiment starts. FIG. 7 is a time chart diagram for explaining the case where the vehicle of the comparative example starts.

Vehicles according to embodiments of the present invention will be specifically described below with reference to the drawings. In addition, this invention is not limited to embodiment described below.

FIG. 1 is a skeleton diagram that schematically shows the vehicle of the embodiment. A vehicle 1 is a hybrid vehicle that includes an engine 2, a first motor 3, and a second motor 4 as power sources. The vehicle 1 is a four-wheel drive vehicle including left and right front wheels 5L and 5R and left and right rear wheels 6L and 6R as drive wheels. In this description, the symbols L and R are omitted when the left and right are not particularly distinguished.

This vehicle 1 is based on a parallel hybrid system and is based on a front engine rear wheel drive system. Therefore, the rear wheels 6 are the main driving wheels and become the driving wheels during two-wheel drive and four-wheel drive. The front wheels 5 are sub-driving wheels and become driven wheels during two-wheel drive running, and drive wheels during four-wheel drive running. The first motor 3 is a motor for main drive, and the second motor 4 is a motor for front/rear distribution. By driving the first motor 3 and the second motor 4 , the power of the power source is transmitted to the front wheels 5 and the rear wheels 6 . In this embodiment, the rear wheels 6 are the first drive wheels and the front wheels 5 are the second drive wheels.

The vehicle 1 also includes a power transmission device 10 that transmits the power of the power source to the drive wheels. The power transmission device 10 includes a clutch 11, a torque converter 12, an automatic transmission 13, a differential device 14, a transmission device 15, a front propeller shaft 16, a rear propeller shaft 17, and a front wheel differential gear mechanism 18. , a rear wheel differential gear mechanism 19, left and right front wheel axles 20L and 20R, and left and right rear wheel axles 21L and 21R. On the front wheel side of the vehicle 1 , left and right front wheel axles 20 L and 20 R are connected to a front wheel differential gear mechanism 18 , and the front wheel differential gear mechanism 18 is connected to a front propeller shaft 16 . On the rear wheel side of the vehicle 1 , left and right rear wheel axles 21 L and 21 R are connected to a rear wheel differential gear mechanism 19 , and the rear wheel differential gear mechanism 19 is connected to a rear propeller shaft 17 .

The clutch 11 is provided between the engine 2 and the torque converter 12 and is a clutch for disconnecting the engine 2 from the driving wheels. The clutch 11 is composed of a hydraulic friction engagement device. When the clutch 11 is in the engaged state, the engine 2 and the torque converter 12 are connected so as to be able to transmit power, and the engine 2 is connected to the driving wheels. When the clutch 11 is in the disengaged state, the power transmission between the engine 2 and the torque converter 12 is disconnected, and the engine 2 is disconnected from the drive wheels. A flywheel 22 is always connected to the engine 2 . The flywheel 22 is provided between the engine 2 and the clutch 11 and includes a damper 22a. The output element of the damper 22a rotates integrally with the input-side engagement element of the clutch 11. As shown in FIG. The output-side engaging element of the clutch 11 rotates integrally with the first motor 3 .

The first motor 3 is a motor that is provided between the clutch 11 and the torque converter 12 and functions as a main power source. The first motor 3 is a first rotary electric machine (first motor/generator) capable of functioning as an electric motor and a generator, and is electrically connected to a battery via an inverter. The first motor 3 includes a rotor 3a, a stator 3b, and a rotor shaft 3c.

The rotor 3a is connected to the output-side engagement element of the clutch 11 so as to rotate integrally therewith. As shown in FIG. 1, the first motor 3 and the clutch 11 are arranged so that their axial positions overlap each other, and the output-side engaging element of the clutch 11 is attached to the inner peripheral portion of the rotor 3a. The stator 3b has a stator core and a stator coil wound around the stator core. The rotor shaft 3c is a rotating shaft that functions as an output shaft of the first motor 3, and rotates integrally with the rotor 3a. Power output from the rotor shaft 3 c is input to the torque converter 12 .

Torque converter 12 is provided between clutch 11 and automatic transmission 13 . This torque converter 12 includes a pump impeller, a turbine runner, and a lockup clutch. The pump impeller rotates integrally with the front cover and rotor shaft 3c. The turbine runner rotates integrally with the turbine shaft and the input shaft of the automatic transmission 13 . A lockup clutch is a hydraulic friction clutch that selectively connects the front cover and the turbine shaft. When the lockup clutch is disengaged, power transmission through hydraulic fluid is allowed between the pump impeller and the turbine runner. When the lockup clutch is engaged, the front cover and the turbine shaft are directly connected so that the rotor shaft 3c and the input shaft of the automatic transmission 13 can rotate integrally.

Thus, when the clutch 11 is engaged, the power output from the engine 2 and the power output from the first motor 3 can be transmitted to the automatic transmission 13 via the torque converter 12 . The power output from the first motor 3 can be transmitted to the automatic transmission 13 via the torque converter 12 even when the clutch 11 is in the released state. The automatic transmission 13 changes the speed of the input power and outputs it from the rotary shaft 23 . The rotating shaft 23 functions as an output shaft of the automatic transmission 13 .

A rear propeller shaft 17 is connected to the rotating shaft 23 . The rotating shaft 23 and the rear propeller shaft 17 are arranged on the same axis and rotate together. Power output from the automatic transmission 13 to the rotary shaft 23 is transmitted from the rear propeller shaft 17 to the rear wheels 6 via the rear wheel differential gear mechanism 19 and the rear wheel axle 21 . A differential gear 14 is connected to the rotating shaft 23 .

The differential gear 14 is a power distribution mechanism that performs a differential action with a plurality of rotating elements and distributes the power of the power source to the front wheels 5 and the rear wheels 6 . The differential gear 14 illustrated in FIG. 1 is a single pinion type planetary gear device. The differential gear 14 has three rotating elements: a sun gear S, a carrier C that supports a plurality of pairs of mutually meshing pinion gears so that they can rotate and revolve, and a ring gear R that meshes with the sun gear S via the pinion gears. ing. In this embodiment, the sun gear S is the first rotating element, the carrier C is the second rotating element, and the ring gear R is the third rotating element.

A first motor 3 , a second motor 4 , a front propeller shaft 16 and a rear propeller shaft 17 are connected to the differential gear 14 . A second motor 4 is connected to the sun gear S, which is the first rotating element. A front propeller shaft 16 is connected to the carrier C, which is the second rotating element. The rear propeller shaft 17 and the first motor 3 are connected to the ring gear R, which is the third rotating element.

Specifically, the first rotating member 24 is connected to the sun gear S, which is the first rotating element, so as to rotate integrally therewith. The first rotating member 24 is a rotating shaft arranged on the same axis as the rotating shaft 23 and the rear propeller shaft 17 , and inputs the power of the second motor 4 to the differential device 14 . The first rotating member 24 functions as an input shaft of the differential device 14 in the power transmission path on the second motor 4 side.

The second motor 4 is a motor that is provided on an axis different from the rotation center axis of the first rotating member 24 and functions as a secondary power source. The second motor 4 is a second rotating electric machine (second motor/generator) capable of functioning as an electric motor and a generator, and is electrically connected to the battery via an inverter. The second motor 4 includes a rotor 4a, a stator 4b, and a rotor shaft 4c that rotates integrally with the rotor 4a.

A reduction gear 25 is provided on the rotor shaft 4c. The rotor shaft 4 c rotates integrally with the rotor 4 a and the reduction gear 25 . The reduction gear 25 meshes with the counter gear 26 . The counter gear 26 meshes with the input gear 27 . The input gear 27 rotates integrally with the first rotating member 24 . A gear train is formed by the reduction gear 25 , the counter gear 26 and the input gear 27 . This gear train may be a gear train with a gear ratio of "1", or may be a reduction gear train with a gear ratio greater than "1". For example, in the case of a reduction gear train, when the power output from the second motor 4 is transmitted to the input gear 27 via the counter gear 26, the rotation of the second motor 4 is changed (reduced) and transmitted. Thus, the second motor 4 is always connected to the sun gear S.

A second rotating member 28 is connected to the carrier C, which is a second rotating element, so as to rotate integrally therewith. The second rotating member 28 functions as an output member of the differential 14 when power is output from the differential 14 to the front propeller shaft 16 . The power output from the differential device 14 to the second rotating member 28 is transmitted from the transmission device 15 to the front wheels 5 via the front propeller shaft 16 , the front wheel differential gear mechanism 18 , and the front wheel axle 20 .

The transmission device 15 is a mechanism that forms a power transmission path for the front wheels, and is provided in the power transmission path between the differential device 14 and the front propeller shaft 16 . This transmission device 15 includes a drive gear 29 , a driven gear 30 and a chain belt 31 .

The drive gear 29 is a rotating member connected to rotate integrally with the second rotating member 28 and functions as an output gear that outputs power to the front propeller shaft 16 . The drive gear 29 is arranged on the same axis as the rotary shaft 23 and the rear propeller shaft 17 and is rotatable relative to the rear propeller shaft 17 . The driven gear 30 is a gear provided integrally with the front propeller shaft 16 . The chain belt 31 is a front wheel drive chain that connects the drive gear 29 and the driven gear 30 . As the drive gear 29 rotates, the driven gear 30 rotates, and the driven gear 30 and the front propeller shaft 16 rotate integrally.

A third rotating member 32 is connected to the ring gear R, which is a third rotating element, so as to rotate integrally therewith. The third rotating member 32 forms a power transmission path between the rotating shaft 23 and the differential gear 14 . That is, when power is transmitted from the first motor 3 to the rear propeller shaft 17 to drive the rear wheels 6, the rotating shaft 23, the rear propeller shaft 17, the third rotating member 32, and the ring gear R rotate together. , the torque for driving the rear wheel 6 acts on the ring gear R.

The vehicle 1 also includes an electronic control unit 100 that controls the vehicle 1 . For example, the electronic control unit 100 includes a microcomputer having a CPU, RAM, ROM, input/output interfaces, and the like. The CPU executes various controls of the vehicle 1 by performing signal processing according to a program stored in advance in the ROM while using the temporary storage function of the RAM.

Signals from various sensors mounted on the vehicle 1 are input to the electronic control unit 100 . For example, an engine rotation speed sensor that detects the rotation speed of the engine 2, a first motor rotation angle sensor that detects the rotation angle of the first motor 3, and a second motor rotation angle sensor that detects the rotation angle of the second motor 4. In addition, signals from a vehicle speed sensor that detects vehicle speed, an accelerator opening sensor that detects accelerator opening, a 4WD selection switch for selecting a four-wheel drive mode by the driver's operation, etc. are input to the electronic control unit 100. . The electronic control unit 100 executes driving control and the like of the vehicle 1 based on the input signal. The electronic control unit 100 outputs a command signal for controlling the engine 2, a command signal for controlling the automatic transmission 13, a command signal for controlling the first motor 3, a command signal for controlling the second motor 4, and the like. be. In other words, the electronic control device 100 is a control device that controls the first motor 3 and the second motor 4 .

In the vehicle 1, since the differential device 14 always performs a differential operation, switching between the stop and drive of the second motor 4 while the first motor 3 is being driven enables the two-wheel drive state and the four-wheel drive state. It is possible to switch between

In the two-wheel drive state, the power of the engine 2 and the power of the first motor 3 are transmitted to the rear wheels 6 without going through the differential gear 14 . Then, the electronic control unit 100 can execute single drive control in which only the first motor 3 is driven while the second motor 4 is stopped. In other words, the vehicle 1 is controlled to the two-wheel drive state by the electronic control unit 100 executing the single-drive control. When executing this single-drive control, the two-wheel drive state by the power of the first motor 3 can be realized even if the clutch 11 is in the disengaged state. Further, the electronic control unit 100 can realize a two-wheel drive state by the power of the engine 2 by driving the engine 2 while controlling the clutch 11 to be in the engaged state.

In the four-wheel drive state, the power of the engine 2 and the power of the first motor 3 are transmitted to the rear wheels 6 without passing through the differential device 14, and the power of the second motor 4 is transmitted through the differential device 14 to the front wheels. 5. During four-wheel drive, the rotational differential between the rear propeller shaft 17 and the front propeller shaft 16 is not limited, so the power of the second motor 4 can be used to control the front-rear distribution. That is, the electronic control unit 100 executes both drive control for driving the first motor 3 and the second motor 4 . Then, the vehicle 1 is controlled to the four-wheel drive state by the electronic control unit 100 executing the dual drive control. In addition, when controlling the vehicle 1 to the four-wheel drive state, the electronic control unit 100 controls the power of the second motor 4 and controls the power of the first motor 3 to control the rear wheel side and the front wheel side. control the distribution of torque in

FIG. 2 is a collinear diagram showing the state of the rotating elements of the differential gear in the four-wheel drive state. In FIG. 2, the first motor 3 is "MG1", the second motor 4 is "MG2", the front propeller shaft 16 is "Fr propeller", the rear propeller shaft 17 is "Rr propeller", and the sun gear S is "S". , the carrier C is "C", the ring gear R is "R", and the gear ratio of the differential gear 14 is "ρ". Further, when the distance between the sun gear S and the carrier C is set to correspond to "1" in the relationship between the vertical axes of the alignment chart, the distance between the carrier C and the ring gear R is the gear ratio ρ The interval corresponds to (=the number of teeth of the sun gear S/the number of teeth of the ring gear R).

As shown in FIG. 2, when the vehicle 1 is in the four-wheel drive state, the torque Tmg2 output from the second motor 4 (hereinafter referred to as second motor torque) acts on the sun gear S, and the carrier C receives the front torque Tmg2. A front propeller torque Tfr transmitted to the propeller shaft 16 acts, and a rear propeller torque Trr transmitted to the rear propeller shaft 17 acts on the ring gear R. The front propeller torque Tfr is the torque of the front propeller shaft 16 . A rear propeller torque Trr is the torque of the rear propeller shaft 17 . Further, when the vehicle 1 is in four-wheel drive, the second motor torque Tmg2, the front propeller torque Tfr, and the rear propeller torque Trr are all positive torques. As a result, the driving torque of the front wheels 5 becomes positive torque, and the driving torque of the rear wheels 6 becomes positive torque.

The positive torque is torque that acts in the direction of increasing the number of rotations in the positive direction (that is, in the direction of bringing the number of rotations in the negative direction closer to 0). Negative torque is torque that acts in the direction of decreasing the number of rotations in the positive direction (that is, in the direction of moving the number of rotations in the negative direction away from 0). In the alignment chart shown in FIG. 2, positive torque is indicated by an upward arrow, and negative torque is indicated by a downward arrow. In the alignment chart, the number of rotations in the positive direction is shown above "0", and the number of rotations in the negative direction is shown below "0".

As shown in FIG. 2, the torque of the sun gear S is represented by the torque input from the second motor 4 side. The torque acting on the sun gear S is obtained by multiplying the gear ratio between the second motor 4 and the sun gear S by the second motor torque Tmg2. For example, when the gear ratio between the second motor 4 and the sun gear S is "1", the torque of the sun gear S is the same as the second motor torque Tmg2.

The torque of the carrier C is represented by the torque of the second motor 4 and the gear ratio ρ of the differential gear 14 . The torque acting on carrier C is the torque acting on front propeller shaft 16 . Therefore, the front propeller torque Tfr is represented by Tfr={(1+ρ)/ρ}×Tmg2.

Furthermore, in the four-wheel drive state, when positive torque from the second motor 4 acts on the sun gear S, negative torque acts on the ring gear R accordingly. That is, negative torque acts on the ring gear R as torque from the second motor 4 . This negative torque is represented by "(1/ρ)×Tmg2".

Therefore, the torque of the ring gear R is represented by the input torque Tin from the first motor 3 side and the negative torque from the second motor 4 . The input torque Tin is positive torque transmitted from the first motor 3 side to the rotating shaft 23 . Since the rotating shaft 23 rotates integrally with the rear propeller shaft 17 and the ring gear R, the torque of the rotating shaft 23 is input to the ring gear R as input torque Tin. Further, a negative torque from the second motor 4 side acts on the ring gear R. Therefore, the rear-operator torque Trr is represented by Trr=Tin-(1/ρ)×Tmg2. Further, in the example shown in FIG. 2, since the input torque Tin, which is positive torque, is larger than the negative torque from the second motor 4 side, the rear propeller torque Trr becomes positive torque. In the four-wheel drive state, the sum of the front propeller torque Tfr and the rear propeller torque Trr is equal to the sum of the input torque Tin and the second motor torque Tmg2.

Further, in the four-wheel drive state, it is possible to increase the front propeller torque Tfr by increasing the second motor torque Tmg2. However, if the second motor torque Tmg2 is made too large in order to increase the front propeller torque Tfr, the negative torque acting on the ring gear R becomes excessive, for example, the negative torque becomes larger than the input torque Tin, and the rear propeller torque Trr becomes negative. It can become torque. When the rear propeller torque Trr becomes negative torque in this way, the driving torque of the front wheels 5 and the driving torque of the rear wheels 6 become torques in opposite directions. Therefore, in the vehicle 1, when power is transmitted via the differential gear 14, the front propeller torque Tfr and the rear propeller torque Trr are not reversed.

Specifically, when executing four-wheel drive control, the electronic control unit 100 controls the power of the first motor 3 and the power of the second motor 4 so that the driving torque of the rear wheels 6 becomes positive torque. . In this case, in order to realize the four-wheel drive state, power must be input to the differential device 14 from the second motor 4 side while power is being input to the differential device 14 from the first motor 3 side. is required. In short, in order to apply positive torque to the carrier C, positive torque must be input to the ring gear R as a reaction force against the torque input to the sun gear S from the second motor 4 . That is, in order to transmit positive torque to the front propeller shaft 16, positive torque must be input to the ring gear R from the first motor 3 side. That is, when power is transmitted to the power transmission path for the front wheels, the sun gear S serves as an input element, the carrier C serves as an output element, and the ring gear R serves as a reaction force element. Therefore, positive torque acts on the carrier C by inputting the second motor torque Tmg2 to the sun gear S while the positive torque from the first motor 3 side is acting on the ring gear R. Since the front propeller shaft 16 is connected to the carrier C, positive torque acting on the carrier C is output to the front propeller shaft 16 .

Further, the electronic control unit 100 can execute an EV mode in which the first motor 3 is driven while the engine 2 is stopped, and an HV mode in which the power of the engine 2 is used to drive the vehicle. The EV mode includes dual drive control and single drive control. In the EV mode, the input torque Tin is based on the torque Tmg1 output from the first motor 3 (hereinafter referred to as first motor torque). That is, when the EV mode is executed, the input torque Tin is represented by the gear ratio between the first motor 3 and the rear propeller shaft 17 and the first motor torque Tmg1.

Also, the electronic control unit 100 can execute the EV mode in consideration of the transmission rate of the power transmission device 10 . In EV running or regeneration using the first motor 3, the torque is transmitted while the lockup clutch of the torque converter 12 is released and the torque is transmitted via the automatic transmission 13, so the efficiency is not high. On the other hand, since the power of the second motor 4 is transmitted without receiving the efficiency of the torque converter 12 and the automatic transmission 13, it is efficient. However, since the power of the second motor 4 is transmitted to the drive wheels by the ring gear R of the differential gear 14 acting as a reaction element, the power of the second motor 4 alone is not transmitted to the drive wheels. Therefore, in four-wheel drive mode, in order to optimize fuel efficiency, the second motor 4 outputs power as much as possible and the power of the first motor 3 is suppressed to maximize efficiency and improve fuel efficiency. . However, the power of the second motor 4 is set within a range in which one of the front and rear wheels does not become a negative torque due to the function of the front-rear distribution.

FIG. 3 is a diagram showing the relationship between the front propeller torque and the rear propeller torque. Note that FIG. 3 shows various torques in the EV mode.

As indicated by an arrow A1 in FIG. 3, by applying the first motor torque Tmg1 to the power transmission device 10, torque is transmitted from the first motor 3 to the rear propeller shaft 17, so that the rear propeller torque Trr becomes positive torque. . For example, in the two-wheel drive state, the forward rear propeller torque Trr acts while the second motor torque Tmg2 is zero. From this state, when the second motor torque Tmg2 is applied to the power transmission device 10, the state is shifted to the four-wheel drive state. By increasing the second motor torque Tmg2, it is possible to increase the front propeller torque Tfr while decreasing the rear propeller torque Trr, as indicated by an arrow A2. In the example shown in FIG. 3, the second motor torque Tmg2 is increased without changing the magnitude of the input torque Tin. That is, by increasing the second motor torque Tmg2 while the first motor torque Tmg1 is constant, the front propeller torque Tfr increases and the rear propeller torque Trr decreases.

Then, it is possible to reduce the rear propeller torque Trr to a range B in which the positive torque can be maintained. This range B is set so that the rear propeller torque Trr is greater than zero and less than a predetermined value. This predetermined value is set to a value that enables the EV running by using the power of the second motor 4 as much as possible for the first motor 3 and the second motor 4 . That is, the range B is a range in which EV traveling can be performed by using the driving force of the second motor torque Tmg2 as much as possible with respect to the first motor torque Tmg1 and the second motor torque Tmg2. It is a range that does not occur. For example, the predetermined value can be set to a value that makes the second motor torque Tmg2 larger than the first motor torque Tmg1. In this case, the range B is set to a range in which the positive torque from the first motor 3 side in the ring gear R can be maintained larger than the negative torque from the second motor 4 side.

Therefore, the electronic control unit 100 controls the first motor torque Tmg1 and the second motor torque Tmg2 so that the rear propeller torque Trr is within the range B, as shown in FIG. In this case, as shown in FIG. 5, the power of the first motor 4 is controlled so that the rear propeller torque Trr does not enter a negative torque region (negative region) so that the power of the second motor 4 can be used as much as possible to enable EV travel. It controls the magnitude of the torque Tmg1 and the magnitude of the second motor torque Tmg2. For example, as shown by the solid line in FIG. 5, the second motor torque Tmg2 is controlled to be greater than the first motor torque Tmg1 in a range where the rear blade torque Trr does not become negative torque. At that time, the electronic control unit 100 controls the rear propeller torque Trr and the A front propeller torque Tfr is calculated. Further, as indicated by the dashed line in FIG. 5, when the rear propeller torque Trr becomes zero, the fuel efficiency is maximized. That is, the efficiency is maximized when the second motor torque Tmg2 is maximized in a region where the rear propeller torque Trr is equal to or greater than zero.

For example, when the vehicle 1 is started, the electronic control unit 100 performs EV start from a state in which the engine 2 is stopped. At that time, the electronic control unit 100 executes both drive controls. As shown in FIG. 6, when the electronic control unit 100 receives a start request while the vehicle 1 is stopped, it starts start control (time t1). In start control, the power of the motor is controlled according to the required driving force. When starting control, the electronic control unit 100 drives only the first motor 3 while the second motor 4 remains stopped. Then, when the power of the first motor 3 increases, the second motor 4 is driven (time t2). At time t2, both drive control is started. After starting to drive the second motor 4, the electronic control unit 100 controls the first motor 3 so as to suppress an increase in the first motor torque Tmg1. On the other hand, the electronic control unit 100 continues increasing the second motor torque Tmg2. Therefore, the second motor torque Tmg2 becomes larger than the first motor torque Tmg1 (time t3). After time t3, the second motor torque Tmg2 is controlled to be larger. Then, starting of the engine 2 is started (time t4). At time t4, engine start control is started. After time t4, the first motor torque Tmg1 and the second motor torque Tmg2 are reduced toward zero while the engine 2 is being started. Then, by starting the engine 2, the required driving force can be satisfied by the power of the engine 2 (time t5).

As described above, according to the embodiment, when the first motor 3 and the second motor 4 respectively output torque, the second motor 4 with high efficiency adds power as much as possible, and the first motor 3 The torque of the rear propeller shaft 17 can be controlled to a positive torque while suppressing the power of the rear propeller shaft 17 . As a result, the driving torque of the front wheels 5 and the driving torque of the rear wheels 6 can be controlled to have the same direction while improving fuel efficiency.

In addition, when the vehicle 1 is started as an EV, the power of the first motor 3 can be suppressed while increasing the power of the second motor 4, thereby improving fuel efficiency. For example, in a comparative example in which the EV is started using only the first motor, as shown in FIG. 7, after driving the first motor, the engine is driven while the second motor is stopped. In this case, from time t1 to time t4, the power transmission path on the side of the first motor with relatively low efficiency is used, and the efficiency is not high. On the other hand, according to the present embodiment, since the power of the second motor 4 is controlled so as to be greater than the power of the first motor 3, efficient power transmission is possible and fuel efficiency is improved.

Note that the vehicle 1 is not limited to a vehicle based on a parallel hybrid. For example, the vehicle 1 may be an electric vehicle in which the engine 1 is not mounted. In this case, the first motor 3 serves as the main power source, and the second motor 4 serves as the secondary power source.

Further, the vehicle 1 is not limited to a vehicle based on a front engine rear wheel drive. For example, the vehicle 1 may be based on front-wheel drive. In this case, the front wheels 5 are the first drive wheels and the rear wheels 6 are the second drive wheels. That is, the main drive wheel is one of the front wheels 5 and the rear wheels 6, and the auxiliary drive wheel is the other drive wheel of the front wheels 5 and the rear wheels 6. As shown in FIG.

Also, the automatic transmission 13 may be a transmission, and its configuration is not particularly limited.

Further, the electronic control unit 100 can perform both drive control not only when the vehicle 1 starts. That is, the dual drive control may be executed not only when the vehicle starts, but also while the vehicle is running.

1 Vehicle 2 Engine 3 First Motor (First Rotating Electric Machine)
4 Second motor (second rotating electric machine)
5, 5R, 5L front wheel (second driving wheel)
6, 6R, 6L rear wheel (first driving wheel)
REFERENCE SIGNS LIST 10 power transmission device 11 clutch 12 torque converter 13 automatic transmission 14 differential device 15 transmission device 16 front propeller shaft (second output shaft)
17 rear propeller shaft (first output shaft)
23 Rotating shaft 24 First rotating member 28 Second rotating member 32 Third rotating member 100 Electronic control device (control device)
C Carrier S Sun gear R Ring gear

Claims (6)

a first rotating electrical machine;
a second rotating electric machine;
a first output shaft coupled to the first drive wheel;
a second output shaft coupled to the second drive wheel;
As three rotating elements, a first rotating element to which the second rotating electrical machine is connected, a second rotating element to which the second output shaft is linked, and a first rotating element to which the first rotating electrical machine and the first output shaft are linked. a differential having a third rolling element;
a control device that controls the first rotating electrical machine and the second rotating electrical machine;
with
When the control device executes dual drive control for driving the first rotating electric machine and the second rotating electric machine, the third rotating element receives positive torque from the first rotating electric machine and the second rotating electric machine. A vehicle that drives the first drive wheel and the second drive wheel in a state where negative torque from an electric machine is applied,
The vehicle, wherein the control device performs control such that the drive torque of the first drive wheel becomes a positive torque when executing the dual drive control. During execution of the dual drive control, the control device controls the power of the first rotating electrical machine and the second rotating electrical machine so that the positive torque acting from the first rotating electrical machine on the third rotating element is greater than the negative torque. The vehicle according to claim 1, wherein the power of the rotating electric machine is controlled. During execution of the dual drive control, the control device controls the power of the first rotating electrical machine within a range in which the positive torque acting from the first rotating electrical machine in the third rotating element can be maintained larger than the negative torque. is decreased, and the power of the second rotating electric machine is increased. During execution of the dual drive control, the control device controls the power of the second rotating electrical machine within a range in which the positive torque acting on the third rotating element from the first rotating electrical machine can be maintained larger than the negative torque. is set larger than the power of the first rotating electric machine. 5. The control device according to any one of claims 1 to 4, wherein, when starting the vehicle, the control device executes start control to drive the second rotating electrical machine after driving the first rotating electrical machine. Vehicles described in paragraph. During execution of the start control, the control device controls the third rotating element so that, after the second rotating electric machine is driven, a positive torque acting from the first rotating electric machine on the third rotating element becomes larger than the negative torque. 6. The vehicle according to claim 5, wherein power of the first rotating electrical machine and power of the second rotating electrical machine are controlled.

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