JP5963738B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to an internal combustion engine as a power source, a first electric motor mechanically connected to the internal combustion engine, a second electric motor mechanically connected to the wheels to drive the wheels, and the first and second electric motors. The present invention relates to a control device for a hybrid vehicle including a battery that is electrically connected to the vehicle.

  Conventionally, as a control device of this type of hybrid vehicle, for example, one disclosed in Patent Document 1 is known. The hybrid vehicle includes an internal combustion engine mechanically coupled to a rear wheel, a generator and an electric motor mechanically coupled to the internal combustion engine and the rear wheel, respectively, and a battery electrically connected to the generator and the electric motor. I have. In the control device, when the internal combustion engine is controlled to obtain the best fuel consumption and the torque of the internal combustion engine controlled in such a manner is larger than the traveling load of the hybrid vehicle, the surplus of the torque of the internal combustion engine with respect to the traveling load The minute (hereinafter referred to as “the engine torque surplus”) is converted into electric power by the generator, and the converted electric power is charged in the battery.

JP-A-9-224304

  As described above, in the conventional control device, the surplus engine torque is converted into electric power by the generator, and the converted electric power is charged in the battery. For this reason, when the traveling load is relatively small, the engine torque surplus becomes relatively large, which may result in excessive power generated by the generator. In this case, an excessive load is applied to the generator. This shortens the life of the generator. In order to prevent such a problem, it is conceivable to limit the generated power of the generator. In that case, the engine torque surplus, that is, the surplus of the torque of the internal combustion engine with respect to the running load is generated by the generator. It cannot be consumed, and the drivability of the vehicle deteriorates because the torque transmitted to the wheels becomes larger than the traveling load.

  The present invention has been made to solve the above-described problems, and can prevent an excessive increase in the generated power of the first motor, thereby extending the life of the first motor and improving drivability. An object of the present invention is to provide a hybrid vehicle control device that can be improved.

In order to achieve the above object, an invention according to claim 1 includes an internal combustion engine 3 as a power source, a first electric motor mechanically coupled to the internal combustion engine 3 (in the embodiment (hereinafter the same applies in this section)). Front motor 4), a second electric motor (first rear motor 41, second rear motor 61) mechanically coupled to the wheels to drive the wheels (left rear wheel WRL, right rear wheel WRR), and first and A control device 1 for a hybrid vehicle V including a battery (battery 7) electrically connected to a second electric motor, wherein the internal combustion engine drives other wheels (left front wheel WFL, right front wheel WFR) different from the wheels. In order to drive, the first wheel required driving force (rear wheel required driving force PRWREQ) required to drive the wheel is mechanically connected to the other wheel and required to drive the other wheel. Second wheel demand drive The wheel required driving force calculating means (ECU 2, step 2 in FIG. 7, step 23 in FIG. 9, step 42 in FIG. 10) for calculating (the front wheel required driving force PFWREQ) and the power of the internal combustion engine 3 were calculated. Internal combustion engine control means (ECU 2, steps 7, 10, 11 in FIG. 7, step 15 in FIG. 8) for controlling the first and second wheel required driving force (all wheel required driving force PAWREQ), and the first electric motor In order to supply the electric power generated by the first electric motor to the second electric motor, first electric motor control means (ECU2, PDU6, Steps 23 to 25 and 28 in FIG. 9 and the second motor control means (ECU2, PDU6) for controlling the second motor supply power, which is the power supplied to the second motor, based on the first wheel required driving force. Step 43 in FIG. 10 and the upper limit value of the electric power that can be generated by the first motor, which is the electric power generated by the first electric motor under the control of the first electric motor control means (front motor power generation). Limiting means (ECU2, PDU6, steps 27 and 31 in FIG. 9) for limiting the power to the upper limit power FGLMT) or less, and the internal combustion engine control means has the first motor generated power limited to the upper limit value or less by the limiting means. (Step 14 in FIG. 8: YES), the amount of power generated by the first motor is reduced by the restriction, so that the power of the internal combustion engine 3 is reduced as compared with the case where the first and second wheel required driving forces are controlled. controlled so as to be (step 17-19), the second motor control means, when the first motor generated power is limited to less than the upper limit value by the restriction means, the first wheel required driving force Based on this, the second electric motor supply power is controlled so that the electric power corresponding to the decrease in the electric power generated by the first electric motor due to the restriction by the restriction means is supplemented by the electric power of the battery (step 43 in FIG. 10).

According to this configuration, the first required wheel driving force required for driving the wheels and the second required wheel driving force required for driving the other wheels are calculated by the required wheel driving force calculating means. At the same time, the power of the internal combustion engine is controlled by the internal combustion engine control means in accordance with the calculated first and second wheel required driving forces. Further, in order to supply the electric power generated by the first motor to the second motor, the power generation by the first motor using the power of the internal combustion engine is controlled by the first motor control means according to the first wheel required driving force. The Furthermore, the second motor supply power, which is the power supplied to the second motor, is controlled by the second motor control means based on the first wheel required driving force.

As described above, the power of the internal combustion engine is controlled according to the first and second wheel required driving forces, and the controlled power of the internal combustion engine is converted into electric power by the first electric motor (power generation), and the first wheel required driving is performed. Based on the force, the electric power generated by the first electric motor can be supplied to the second electric motor, returned to the motive power by the second electric motor, and transmitted to the wheels. Therefore, the driving force transmitted from the internal combustion engine to the wheels via the first and second electric motors can be appropriately controlled based on the first wheel required driving force. Further, the first motor generated power, which is the generated power generated by the first motor by the control by the first motor control means, is limited by the limiting means to be equal to or lower than the upper limit value of the power that can be generated by the first motor. . Thereby, the excessive increase of the electric power generated by the first motor can be prevented, and thereby the life of the first electric motor can be extended.

Further, due to the limitation of the first motor generated power by the limiting means, the second motor supply power supplied from the first motor to the second motor is reduced by this limitation. According to the above-described configuration, when the first motor generated power is limited to the upper limit value or less by the limiting means, the first motor generated power is reduced by the limitation by the limiting means based on the first wheel required driving force. The second electric motor supply power is controlled so that the electric power of the minute is supplemented by the electric power of the battery. As a result, it is possible to appropriately control the second motor supply power without deficiency based on the first wheel required driving force while the first motor generated power is limited, so that the second motor is transmitted to the wheels. The driving force can be appropriately controlled, and consequently the drivability of the hybrid vehicle can be improved. In addition, when the first motor generated power is limited to the upper limit value or less by the limiting means, the power of the internal combustion engine is reduced to the first and second wheel required driving force by the amount that the first motor generated power is reduced by the limitation. Accordingly, the control is performed so as to reduce the control amount. As a result, the power of the internal combustion engine can be reduced in accordance with the limited first electric motor generated power while the first electric motor generated electric power is limited.

It is a figure showing roughly the hybrid vehicle to which the control device by this embodiment is applied. It is a skeleton figure which shows a rear-wheel drive device roughly. It is a block diagram which shows ECU etc. of a control apparatus. It is a collinear diagram which shows the relationship of the rotational speed between the various rotation elements of a rear-wheel drive device, and a right-and-left rear wheel, and the balance of torque about a drive mode. It is a collinear diagram which shows the relationship of the rotational speed between the various rotation elements of a rear-wheel drive device, and a right-and-left rear wheel, and the balance of torque about in regeneration mode. It is a collinear diagram which shows the relationship of the rotational speed between the various rotation elements of a rear-wheel drive device and a left-and-right rear wheel, and a torque balance relationship in the left-right wheel torque difference mode. It is a flowchart which shows the process for controlling the engine performed by ECU. It is a flowchart which shows the continuation of the process shown in FIG. It is a flowchart which shows the process for controlling the front motor performed by ECU. It is a flowchart which shows the process for controlling the 1st and 2nd rear motor performed by ECU. It is a figure which shows roughly the relationship of the magnitude | size of various parameters, such as all-wheel request | requirement driving force. It is a flowchart which shows the RELMT calculation process performed by ECU. FIG. 13 is a timing chart showing an operation example of the processing shown in FIGS. 9, 10 and 12. FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. A hybrid vehicle V shown in FIG. 1 is a four-wheel vehicle having left and right front wheels WFL, WFR and left and right rear wheels WRL, WRR. The hybrid vehicle V includes a front wheel drive device DFS for driving the front wheels WFL, WFR. A rear wheel drive device DRS for driving the rear wheels WRL and WRR is mounted. Hereinafter, the left and right front wheels WFL, WFR and the left and right rear wheels WRL, WRR are collectively referred to as “front wheels WFL, WFR” and “rear wheels WRL, WRR”, respectively.

  Since the front wheel drive device DFS is the same as that disclosed in Japanese Patent No. 5362922 by the present applicant, its configuration and operation will be briefly described below. The front wheel drive device DFS is an internal combustion engine (hereinafter referred to as “engine”) 3 as a power source, a front motor 4 constituted by an electric motor capable of generating electricity, and the power of the engine 3 and the front motor 4 are shifted, and the front wheels WFL, A transmission 5 for transmitting to the WFR is included.

  The engine 3 is a gasoline engine having a plurality of cylinders, and the intake air amount, fuel injection amount, fuel injection timing, ignition timing, and the like are controlled by an ECU 2 described later of the control device 1 shown in FIG. As is well known, the intake air amount is supplied via a throttle valve (not shown), the fuel injection amount and fuel injection timing are supplied via a fuel injection valve (not shown), and the ignition timing is indicated by an ignition plug (not shown). Are controlled respectively.

  The front motor 4 is a brushless DC motor, and includes a stator composed of a three-phase coil or the like, and a rotor composed of a magnet (not shown). The stator is electrically connected to a chargeable / dischargeable battery 7 via a power drive unit (hereinafter referred to as “PDU”) 6. The PDU 6 is composed of an electric circuit such as an inverter, and is electrically connected to the ECU 2 (see FIG. 3).

  In the front motor 4, when electric power is supplied from the battery 7 to the stator via the PDU 6 by the control of the PDU 6 by the ECU 2, this electric power is converted into motive power and the rotor rotates (powering). In this case, the power of the rotor is controlled by controlling the electric power supplied to the stator. In addition, when the rotor is rotated by power input while power supply to the stator is stopped, the power input to the rotor is converted into power by the control of the PDU 6 by the ECU 2 to generate power. The generated electric power is charged in the battery 7 or supplied to first and second rear motors 41 and 61 (to be described later) of the rear wheel drive device DRS.

  The hybrid vehicle V is equipped with an auxiliary machine 8 including a compressor of an air conditioner and a 12V battery (not shown). The auxiliary machine 8 is connected to the PDU 6 and the 12V battery is a DC / DC converter (see FIG. (Not shown) and electrically connected to the stator of the front motor 4 and the battery 7. The auxiliary machine 8 is supplied with the electric power generated by the front motor 4 and the electric power of the battery 7. The electric power supplied to the auxiliary machine 8 is controlled by the ECU 2 via the PDU 6.

  The transmission 5 is constituted by a so-called dual clutch transmission. Although not shown, the transmission 5 includes a first input shaft connected to the engine 3 via the first clutch, a planetary gear device disposed between the front motor 4 and the first input shaft, and a second clutch. A second input shaft connected to the engine 3 via the output shaft, an output shaft parallel to the first and second input shafts, a plurality of input gears rotatably provided on the first and second input shafts, and an output shaft And a plurality of output gears meshed with the plurality of input gears, one of the plurality of input gears is selectively connected to the first or second input shaft, and the input gear and the gear by the output gear meshing with the input gear It has a synchronizer that sets the stage.

  With the above configuration, the ECU 2 controls the first and second clutches and the synchronizer, etc., so that the power of the engine 3 (hereinafter referred to as “engine power”) according to the connection / disconnection state of the first and second clutches. And / or the power of the front motor 4 is selectively input to the first input shaft or the engine power is input to the second input shaft. The input power is output to the output shaft in a state of being shifted at a predetermined gear ratio by the gear set by the synchronizer, and further, via the final gear 9 and the left and right front drive shafts SFL, SFR, It is transmitted to the left and right front wheels WFL, WFR.

  As shown in FIG. 2, the rear wheel drive device DRS includes a first rear motor 41, a first planetary gear device 51, a second rear motor 61, and a second planetary gear device 71. The first rear motor 41, the first planetary gear device 51, the second planetary gear device 71, and the second rear motor 61 are arranged in this order from the left side between the left and right rear wheels WRL, WRR. The rear drive shafts SRL and SRR are provided coaxially. The left and right rear drive shafts SRL, SRR are rotatably supported by bearings (not shown), and one end portions thereof are coupled to the left and right rear wheels WRL, WRR, respectively.

  Similar to the front motor 4, the first rear motor 41 is a brushless DC motor configured as a so-called motor generator, and includes a stator 42 and a rotatable rotor 43. The stator 42 is attached to a casing CA fixed to the hybrid vehicle V, and is electrically connected to the stator of the front motor 4 and the battery 7 via the PDU 6 described above. The rotor 43 is integrally attached to the hollow rotating shaft 44. The rotation shaft 44 is relatively rotatably disposed outside the left rear drive shaft SRL and is rotatably supported by a bearing (not shown).

  In the first rear motor 41, when the electric power from the battery 7 or the electric power generated by the front motor 4 is supplied to the stator 42 via the PDU 6 under the control of the PDU 6 by the ECU 2, the electric power is converted into power accordingly. Then, the rotor 43 rotates (power running). In this case, the power of the rotor 43 is controlled by controlling the power supplied to the stator 42. Further, when the rotor 43 is rotated by the input of power while the power supply to the stator 42 is stopped, the power input to the rotor 43 is converted into electric power by the control of the PDU 6 by the ECU 2 to generate power. The battery 7 is charged with the generated electric power.

  The first planetary gear device 51 is for decelerating the power of the first rear motor 41 and transmitting it to the left rear wheel WRL. The first sun gear 52, the first ring gear 53, the double pinion gear 54, and the first carrier 55 are used. have. The first sun gear 52 is integrally attached to the rotary shaft 44 described above, and is rotatable integrally with the rotor 43 of the first rear motor 41. The first ring gear 53 has a larger number of teeth than the first sun gear 52 and is integrally attached to the hollow rotating shaft 81. The rotating shaft 81 is rotatably supported by a bearing (not shown). The double pinion gear 54 integrally includes a first pinion gear 54a and a second pinion gear 54b, and the number thereof is three (only two are shown). The double pinion gear 54 is rotatably supported by the first carrier 55, and the first pinion gear 54 a meshes with the first sun gear 52 and the second pinion gear 54 b meshes with the first ring gear 53. The first carrier 55 is integrally attached to the other end portion of the left rear drive shaft SRL, and is rotatable integrally with the left rear drive shaft SRL.

  Since the second rear motor 61 and the second planetary gear device 71 are configured in the same manner as the first rear motor 41 and the first planetary gear device 51, the configuration will be briefly described below. The second rear motor 61 and the second planetary gear device 71 are provided symmetrically with the first rear motor 41 and the first planetary gear device 51 with a one-way clutch 83 described later as a center. The stator 62 of the second rear motor 61 is attached to the casing CA and is electrically connected to the stator of the front motor 4, the battery 7 and the stator 42 of the first rear motor 41 via the PDU 6. Further, the rotor 63 of the second rear motor 61 is integrally attached to the hollow rotating shaft 64. The rotation shaft 64 is relatively rotatably disposed outside the right rear drive shaft SRR and is rotatably supported by a bearing (not shown).

  In the second rear motor 61, when the electric power of the battery 7 and the electric power generated by the front motor 4 are supplied to the stator 62 through the PDU 6 by the control of the PDU 6 by the ECU 2, the electric power is converted into power accordingly. The rotor 63 rotates (power running). In this case, the power of the rotor 63 is controlled by controlling the power supplied to the stator 62. Further, when the rotor 63 is rotated by the input of power while the power supply to the stator 62 is stopped, the power input to the rotor 63 is converted into electric power by the control of the PDU 6 by the ECU 2 to generate power. The battery 7 is charged with the generated electric power.

  The second planetary gear device 71 is for decelerating the power of the second rear motor 61 and transmitting it to the right rear wheel WRR. The second sun gear 72, the second ring gear 73, the double pinion gear 74, and the second carrier 75 are used. have. The number of teeth of second sun gear 72, second ring gear 73, and double pinion gear 74 is set to be the same as the number of teeth of first sun gear 52, first ring gear 53, and double pinion gear 54, respectively.

  The second sun gear 72 is integrally attached to the rotary shaft 64 described above, and is rotatable integrally with the rotor 63 of the second rear motor 61. The second ring gear 73 has a larger number of teeth than the second sun gear 72 and is integrally attached to the hollow rotating shaft 82. The rotating shaft 82 is rotatably supported by a bearing (not shown), and opposes the rotating shaft 81 in the axial direction with a slight gap. The double pinion gear 74 is rotatably supported by the second carrier 75, and the first pinion gear 74 a meshes with the second sun gear 72 and the second pinion gear 74 b meshes with the second ring gear 73. The second carrier 75 is integrally attached to the other end portion of the right rear drive shaft SRR, and is rotatable integrally with the right rear drive shaft SRR.

  The rear wheel drive device DRS further includes a one-way clutch 83 and a hydraulic brake 84. The one-way clutch 83 has an inner race 83a and an outer race 83b, and is disposed between the first and second planetary gear devices 51 and 71. In FIG. 2, for convenience of illustration, the inner race 83a is drawn on the outer side, and the outer race 83b is drawn on the inner side. The inner race 83a is engaged with the rotary shafts 81 and 82 described above, whereby the inner race 83a, the rotary shafts 81 and 82, and the first and second ring gears 53 and 73 are rotatable together. The outer race 83b is attached to the casing CA. The one-way clutch 83 connects the rotary shafts 81 and 82 to the casing CA when the reverse power is transmitted to the rotary shafts 81 and 82, thereby connecting the rotary shafts 81 and 82, the first and second ring gears 53 and 73. When power for forward rotation is transmitted to the rotary shafts 81 and 82 while preventing reverse rotation, the rotary shafts 81 and 82, the first and second ring gears are blocked by blocking between the rotary shafts 81 and 82 and the casing CA. 53, 73 normal rotation is allowed.

  The hydraulic brake 84 is composed of a multi-plate clutch, is attached to the casing CA and the rotating shafts 81 and 82, and is disposed on the outer periphery of the first and second planetary gear devices 51 and 71. The hydraulic brake 84 is controlled by the ECU 2 to select a braking operation for braking the first and second ring gears 53 and 73 and a rotation allowing operation for allowing the first and second ring gears 53 and 73 to rotate. Run it. The braking force of the hydraulic brake 84 is controlled by the ECU 2.

  Further, as shown in FIG. 3, the CRK signal is input to the ECU 2 from the crank angle sensor 21. This CRK signal is a pulse signal output at every predetermined crank angle as the crankshaft (not shown) of the engine 3 rotates. The ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal. Further, the ECU 2 receives a detection signal indicating the rotation speed (hereinafter referred to as “front motor rotation speed”) NFM of the front motor 4 from the motor rotation speed sensor 22 from the current / voltage sensor 23 to the current input / output to / from the battery 7. A detection signal representing a voltage value is input. The ECU 2 calculates the state of charge SOC of the battery 7 based on this detection signal.

  Further, the ECU 2 receives from the wheel speed sensor 25 a detection signal indicating the accelerator opening AP, which is the depression amount of an accelerator pedal (not shown) of the hybrid vehicle V, from the accelerator opening sensor 24, and the rotation of the front wheels WFL, WFR. Detection signals representing the number (hereinafter referred to as “front wheel rotational speed”) NWF and the rotational speed of the rear wheels WRL and WRR (hereinafter referred to as “rear wheel rotational speed”) NWR are input. The ECU 2 calculates the vehicle speed VP of the hybrid vehicle V based on the detected front wheel speed NWF and rear wheel speed NWR. Further, the ECU 2 receives from the gradient sensor 26 a detection signal indicating the inclination angle of the road surface on which the hybrid vehicle V is traveling.

  The ECU 2 is composed of a microcomputer including an I / O interface, a CPU, a RAM, a ROM, and the like, and drives the front wheels in accordance with a control program stored in the ROM according to the detection signals from the various sensors 21 to 26 described above. The operation of the hybrid vehicle V including the operations of the device DFS and the rear wheel drive device DRS is controlled.

  The operation mode of the front-wheel drive device DFS includes an ENG traveling mode in which only the engine 3 is used as a power source for the hybrid vehicle V, an EV traveling mode in which only the front motor 4 is used as a power source, and the engine 3 is assisted by the front motor 4. Assist travel mode, charging travel mode in which battery 7 is charged by front motor 4 using part of engine power, and deceleration in which battery 7 is charged by front motor 4 using travel energy during deceleration travel of hybrid vehicle V Includes regeneration mode. The operation of the front wheel drive device DFS in each operation mode is controlled by the ECU 2.

  Further, the operation mode of the rear wheel drive device DRS includes a drive mode, a regeneration mode, a left and right wheel torque difference mode, and the like. The operation of the rear wheel drive device DRS in each operation mode is controlled by the ECU 2. Hereinafter, these operation modes will be described in order.

[Drive mode]
This drive mode is an operation mode in which the left and right rear wheels WRL, WRR are driven by the power of the first and second rear motors 41, 61. In the drive mode, the first and second rear motors 41 and 61 perform power running and control the electric power supplied to both 41 and 61. Further, when the left and right rear wheels WRL, WRR are rotated forward, the rotors 43, 63 of the first and second rear motors 41, 61 are rotated forward, and the first and second ring gears 53, 73 are driven by the hydraulic brake 84. Brake. FIG. 4 shows an example of the rotational speed relationship and the torque balance relationship between the various rotating elements when the left and right rear wheels WRL, WRR are rotated forward during the drive mode.

  As is apparent from the connection relationship between the various rotary elements described above, the rotation speed of the first sun gear 52 is equal to the rotation speed of the first rear motor 41 (rotor 43), and the rotation speed of the first carrier 55 is The rotational speed of the rear wheel WRL and the rotational speed of the first ring gear 53 are equal to the rotational speed of the second ring gear 73, respectively. The rotation speed of the second sun gear 72 is equal to the rotation speed of the second rear motor 61 (rotor 63), and the rotation speed of the second carrier 75 is equal to the rotation speed of the right rear wheel WRR. As is well known, the rotational speed of the first sun gear 52, the rotational speed of the first carrier 55, and the rotational speed of the first ring gear 53 are in a collinear relationship that is located on the same straight line in the collinear diagram. The first sun gear 52 and the first ring gear 53 are located on both outer sides of the first carrier 55. This also applies to the second sun gear 72, the second carrier 75, and the second ring gear 73.

  From the above, the relationship between the rotational speeds of the various rotating elements is expressed as shown in the alignment chart shown in FIG. In the same figure and other collinear charts described later, the distance from the horizontal line indicating value 0 to the white circle on the vertical line corresponds to the number of rotations of each rotating element. In FIG. 4, TM1 is an output torque of the first rear motor 41 generated in accordance with power running (hereinafter referred to as “first rear motor power running torque”), and TM2 of the second rear motor 61 generated in accordance with power running. Output torque (hereinafter referred to as “second rear motor power running torque”). RRL is the reaction torque of the left rear wheel, RRR is the reaction torque of the right rear wheel WRR, and ROW is the reaction torque of the one-way clutch 83.

  As described above, the one-way clutch 83 is configured to prevent reverse rotation of the first and second ring gears 53 and 73. As is clear from FIG. 4, the first rear motor power running torque TM1 acts to cause the first sun gear 52 to rotate in the forward direction and to actuate the first ring gear 53 in the reverse direction. As described above, the first rear motor power running torque TM1 uses the reaction torque ROW of the one-way clutch 83 acting on the first ring gear 53 as a reaction force, and is applied to the left rear wheel WRL via the first carrier 55 and the left rear drive shaft SRL. As a result, the left rear wheel WRL is driven. Similarly, the second rear motor power running torque TM2 uses the reaction force torque ROW of the one-way clutch 83 acting on the second ring gear 73 as a reaction force, and is applied to the right rear wheel WRR via the second carrier 75 and the right rear drive shaft SRR. Communicated. As a result, the right rear wheel WRR is driven.

[Regeneration mode]
In this regeneration mode, while the hybrid vehicle V is traveling at a reduced speed, the first and second rear motors 41 and 61 generate electric power (regeneration) using the travel energy of the hybrid vehicle V, and the battery 7 is charged with the regenerated power. This is an operation mode. In the regeneration mode, the electric power regenerated by the first and second rear motors 41 and 61 is controlled, and the first and second ring gears 53 and 73 are braked by the hydraulic brake 84. FIG. 5 shows the rotational speed relationship and the torque balance relationship between the various rotary elements in the regeneration mode. In the figure, BM1 is an output (braking) torque of the first rear motor 41 (hereinafter referred to as “first rear motor regeneration torque”) generated along with regeneration, and BM2 is a second rear motor 61 generated along with regeneration. Output (braking) torque (hereinafter referred to as “second rear motor regenerative torque”). TRL is the inertia torque of the left drive wheel WRL, TRR is the inertia torque of the right drive wheel WRR, and RBR is the reaction force torque of the hydraulic brake 84.

  As is apparent from FIG. 5, the first and second rear motor regenerative torques BM1 and BM2 transmitted to the first and second sun gears 52 and 72, respectively, are obtained by using the reaction force torque RBR of the hydraulic brake 84 as a reaction force. And the second carriers 55 and 75, respectively, and further transmitted to the left and right rear wheels WRL and WRR via the left and right rear drive shafts SRL and SRR. As a result, the left and right rear wheels WRL, WRR are braked.

[Right and left wheel torque difference mode]
This left and right wheel torque difference mode is an operation mode that causes a torque difference between the left and right rear wheels WRL and WRR when the hybrid vehicle V turns. In the left and right wheel torque difference mode, the first and second rear motors 41 and 61 perform power running on one side and regenerate on the other side, and control the electric power supplied to one side and the electric power regenerated on the other side. The first and second ring gears 53 and 73 are braked. FIG. 6 shows the rotational speed relationship and the torque balance relationship between the various types of rotating elements when the first rear motor 41 performs power running and the second rear motor 61 performs regeneration. Various parameters in the figure are as described with reference to FIGS. 4 and 5.

  As is clear from FIG. 6 and the above description, the first rear motor power running torque TM1 is transmitted to the left rear wheel WRL via the first planetary gear unit 51, whereby the left rear wheel WRL is driven. At the same time, the second rear motor regeneration torque BM2 is transmitted to the right rear wheel WRR via the second planetary gear device 71, whereby the right rear wheel WRR is braked. As a result, reverse torque is generated between the left and right rear wheels WRL and WRR, and a counterclockwise yaw moment is generated in the hybrid vehicle V.

  Contrary to the above, when the first rear motor 41 performs regeneration and the second rear motor 61 performs power running, a clockwise yaw moment is generated in the hybrid vehicle V.

  Further, the all-wheel drive mode is set as the operation mode of the entire front wheel drive device DFS and rear wheel drive device DRS. This all-wheel drive mode is an operation mode for driving all the wheels WFL, WFR, WRL, and WRR of the hybrid vehicle V. The operation of the front wheel drive device DFS and the rear wheel drive device DRS in the all-wheel drive mode is controlled by the ECU 2.

  The operation in the all-wheel drive mode is executed when the hybrid vehicle V is slipping, accelerating, or traveling uphill. Whether or not the vehicle is slipping is determined based on the difference between the detected front wheel rotational speed NWF and the rear wheel rotational speed NWR. Further, whether or not the vehicle is accelerating is determined based on the detected accelerator opening AP. Further, whether or not the vehicle is traveling on an uphill is determined based on the detected inclination angle of the road surface.

  During the all-wheel drive mode, basically, a part of the engine power is used to generate power with the front motor 4, and the power generated by the front motor 4 is supplied to the first and second rear motors 41 and 61. As a result, part of the engine power is transmitted to the rear wheels WRL and WRR via the front motor 4, the PDU 6 and the first and second rear motors 41 and 61, and the rest of the engine power is transmitted to the front wheels WFL and WFR. Is transmitted to. Further, during the all-wheel drive mode, the electric power generated by the front motor 4 is supplied to the auxiliary machine 8 in addition to the first and second rear motors 41 and 61, and the battery 7 is connected to the front motor 4 and the auxiliary machine 8, It functions as a buffer for adjusting the transmission and reception of electric power between the first and second rear motors 41 and 61. For example, when the power generated by the front motor 4 is insufficient with respect to the power to be supplied to the auxiliary machine 8, the first and second rear motors 41, 61, the shortage is supplemented by the power of the battery 7.

  Hereinafter, a process for controlling the front wheel drive device DFS and the rear wheel drive device DRS during the all-wheel drive mode, which is executed by the ECU 2, will be described with reference to FIGS. In these processes, the engine 3, the front motor 4, the first and second rear motors are set so that the driving force transmitted to the entire front wheels WFL, WFR and the rear wheels WRL, WRR becomes the all-wheel required driving force PAWREQ described later. 41 and 61 are cooperatively controlled. In the following description, the first and second rear motors 41 and 61 are collectively referred to as “rear motors 41 and 61” as appropriate.

  7 and 8 show a process for controlling the engine 3 during the all-wheel drive mode. This process is repeatedly executed at a predetermined control cycle (for example, 10 msec). First, in step 1 of FIG. 7 (shown as “S1”, the same applies hereinafter), it is determined whether or not the first completion flag F_DONE1 is “1”. Details of the first completion flag F_DONE1 will be described later. When the answer to step 1 is NO (F_DONE1 = 0), the all-wheel required driving force PAWREQ is calculated (step 2). This all-wheel required driving force PAWREQ is a driving force required for the engine 3 and the rear motors 41 and 61 to drive the entire front wheels WFL and WFR and the rear wheels WRL and WRR. The calculated vehicle speed VP and accelerator It is calculated by searching a predetermined map (not shown) according to the opening degree AP.

  Next, the auxiliary machine required driving force PAC is calculated (step 3). This auxiliary machine necessary driving force PAC is a driving force required for power supply from the front motor 4 to the auxiliary machine 8, and the ON / OFF state of the auxiliary machine 8 detected by a sensor (not shown). Is calculated based on Next, the electric path loss power PEP is calculated (step 4). As described above, during the all-wheel drive mode, a part of the engine power is transmitted to the rear wheels WRL and WRR, and the transmission of the power is once converted into electric power and then transmitted back to the power. This is done by a so-called electric path. In this electric path, a loss (power generation efficiency) when power is converted into electric power by the front motor 4 and a loss (power transmission efficiency) when the converted electric power is supplied to the rear motors 41 and 61 via the PDU 6. A loss (power running efficiency) occurs when electric power supplied to the rear motors 41 and 61 is converted into power. The electric path loss power PEP is a value obtained by converting these losses into power, and is calculated by searching a predetermined map (not shown) according to a rear motor target power ERMOBJ described later.

  In step 5 following step 4, it is determined whether or not the assist control flag F_ASSI is “1”. The assist control flag F_ASSI is set to “1” during the execution of the rear motor assist control. This rear motor assist control is a control for assisting the engine 3 with the rear motors 41 and 61, and when the hybrid vehicle V is accelerated or traveling uphill, when the all-wheel required driving force PAWREQ is relatively large. To be executed. In the rear motor assist control, in addition to the power generated by the front motor 4, the power of the battery 7 is supplied to the rear motors 41 and 61.

  If the answer to step 5 is YES (F_ASSI = 1) and the rear motor assist control is being executed, the rear motor assist driving force PAS is calculated (step 6). The rear motor assist driving force PAS is obtained by converting the electric power supplied from the battery 7 to the rear motors 41 and 61 during the execution of the rear motor assist control into power, and the all-wheel required driving force calculated in step 2 above. Based on PAWREQ, it is calculated by searching a predetermined map (not shown). In this map, the rear motor assist driving force PAS is set to a larger value as the all-wheel required driving force PAWREQ is larger.

In Step 7 following Step 6 above, the all-wheel required driving force PAWREQ, the auxiliary required driving force PAC and the electric path loss power PEP calculated in Steps 2 to 4 and the rear motor assist driving calculated in Step 6 are obtained. Using the force PAS, the provisional value PENREQT of the engine required driving force is calculated by the following equation (1), and the process proceeds to Step 12 described later. The provisional value PENREQT of the engine required driving force is a provisional value of the driving force required for the engine 3.
PENREQT ← PAWREQ + PAC + PEP-PAS (1)

  On the other hand, when the answer to step 5 is NO (F_ASSI = 0) and the rear motor assist control is not being executed, it is determined whether or not the battery charge control flag F_CHAR is “1” (step 8). The battery charge control flag F_CHAR is set to “1” during the execution of the battery charge control. This battery charging control is a control for charging a part of the electric power generated by the front motor 4 using a part of the engine power to the battery 7, and the calculated charging state SOC of the battery 7 is relatively small. And, it is executed when the all-wheel required driving force PAWREQ is relatively small.

  If the answer to step 8 is YES (F_CHAR = 1) and the battery charge control is being executed, the required drive power PCH is calculated (step 9). This required driving power PCH is a value obtained by converting the electric power charged in the battery 7 during the execution of the battery charging control into motive power. Based on the all-wheel required driving power PAWREQ calculated in step 2, a predetermined map is obtained. Calculated by searching (not shown). In this map, the required charging driving force PCH is set to a larger value as the all-wheel required driving force PAWREQ is smaller.

In Step 10 following Step 9 above, the all-wheel required driving force PAWREQ, the accessory required driving force PAC, and the electric path loss power PEP calculated in Steps 2 to 4, respectively, and the required charging driving force calculated in Step 9 are obtained. Using PCH, the provisional value PENREQT of the engine required driving force is calculated by the following equation (2), and the process proceeds to Step 12.
PENREQT ← PAWREQ + PAC + PEP + PCH (2)

On the other hand, when the answer to step 8 is NO (F_CHAR = 0), that is, when the rear motor assist control is not being executed and when the battery charge control is not being executed, all the wheels calculated in steps 2 to 4 are calculated. Using the required driving force PAWREQ, the accessory required driving force PAC, and the electric path loss power PEP, the provisional value PENREQT of the engine required driving force is calculated by the following equation (3) (step 11), and the process proceeds to step 12.
PENREQT ← PAWREQ + PAC + PEP (3)

  In this step 12, assuming that the calculation of the provisional value PENREQT of the engine required driving force is completed, the first completion flag F_DONE1 is set to “1” to indicate that, and the process proceeds to step 13 in FIG. By executing step 12, the answer to step 1 becomes YES (F_DONE1 = 1). In this case, the steps 2 to 12 are skipped and the process proceeds to step 13. In Step 13, it is determined whether or not the second completion flag F_DONE2 is “1”. The second completion flag F_DONE2 indicates that the calculation of the front motor target generated power EFMOBJ by the process shown in FIG. Details thereof will be described later. When the answer to step 13 is NO (F_DONE2 = 0), that is, when the calculation of the front motor target generated power EFMOBJ is not completed, the present process is terminated.

  On the other hand, when the answer to step 13 is YES (F_DONE2 = 1) and the calculation of the front motor target generated power EFMOBJ is completed, it is determined whether or not the front motor power generation limiting flag F_FMLMT is “1” ( Step 14). The front motor power generation limiting flag F_FMLMT is “1” when the power generation power of the front motor 4 (hereinafter referred to as “front motor power generation power”) is limited to the front motor power generation upper limit power FGLMT in the process shown in FIG. Is set to Details thereof will be described later.

  When the answer to step 14 is NO (F_FMLMT = 0), that is, when the front motor power generation power is not limited to the front motor power generation upper limit power FGLMT, the engine required driving force calculated in step 7, 10 or 11 is The provisional value PENREQT is set as it is as the engine required driving force PENREQ (step 15). Next, the first and second completion flags F_DONE1 and F_DONE2 are reset to “0” (step 16), and this process ends.

  On the other hand, when the answer to step 14 is YES (F_FMLMT = 1) and the front motor power generation power is limited to the front motor power generation upper limit power FGLMT, the front motor power generation upper limit power is calculated from a provisional value EFMOBJT of the front motor target power generation power described later. By subtracting FGLMT, the upper limit power deviation ΔEFM is calculated (step 17). Next, a power map correction term COΔEFM is calculated by searching a predetermined map (not shown) based on the calculated upper limit power deviation ΔEFM (step 18). This power deviation correction term COΔEFM is a value obtained by converting the upper limit power deviation ΔEFM into power.

  Next, the engine required driving force PENREQ is calculated by subtracting the power deviation correction term COΔEFM calculated in step 18 from the provisional value PENREQT of the engine required driving force calculated in step 7, 10 or 11. Together with (Step 19), Step 16 is executed, and this process is terminated.

  As described above, according to this process, the engine 3 is requested according to the all-wheel required driving force PAWREQ that is a driving force required to drive the entire front wheels WFL, WFR and the rear wheels WRL, WRR. The provisional value PENREQT of the required engine driving force is calculated (steps 7, 10, and 11). When the front motor power generation power is not limited to the front motor power generation upper limit power FGLMT (step 14: NO), the provisional value PENREQT of the engine required driving force is set as it is as the engine required driving force PENREQ (step). 15).

  On the other hand, when the front motor power generation power is limited to the front motor power generation upper limit power FGLMT (step 14: YES), the power deviation correction term COΔEFM is subtracted from the provisional value PENREQT of the engine required driving force. The required driving force PENREQ is calculated (step 19). Thus, the engine required driving force PENREQ is equivalent to a deviation (upper limit power deviation ΔEFM) between the provisional value EFMOBJT of the front motor target generated power and the front motor power generation upper limit power FGLMT from the provisional value PENREQT of the engine required driving force. Calculated to a value obtained by subtracting power.

  When the calculation of the engine required driving force PENREQ is completed by executing step 15 or 19, the intake air amount of the engine 3 is controlled based on the calculated engine required driving force PENREQ, so that the engine power is Control is performed to achieve the required driving force PENREQ. As described above, the engine power is controlled according to the all-wheel required driving power PAWREQ, and is further controlled according to the limited front motor generated power while the front motor generated power is limited.

  Further, as the calculation of the engine required driving force PENREQ is completed, the first and second completion flags F_DONE1 and F_DONE2 are both reset to “0” (step 16), whereby the provisional value PENREQT of the engine required driving force and the like The various parameters are calculated again. The first and second completion flags F_DONE1 and F_DONE2 are reset to “0” when the engine 3 is started.

  Next, processing for controlling the front motor 4 during the all-wheel drive mode will be described with reference to FIG. This process is repeatedly executed at the control cycle, similarly to the processes shown in FIGS. First, in step 21 of FIG. 9, it is determined whether or not the second completion flag F_DONE2 described above is “1”. When the answer to step 21 is NO, it is determined whether or not the first completion flag F_DONE1 set in step 12 or 16 of FIG. 7 is “1” (step 22). When this answer is NO (F_DONE1 = 0), this process is ended as it is.

  On the other hand, when the answer to step 22 is YES (F_DONE1 = 1), that is, when the calculation of the provisional value PENREQT of the engine required driving force is completed, the all-wheel required driving force calculated in step 2 of FIG. Based on PAWREQ, front wheel required driving force PFWREQ is calculated (step 23). The front wheel required driving force PFWREQ is a driving force required for the engine 3 to drive the front wheels WFL and WFR, and the all wheel required driving force PAWREQ is multiplied by a predetermined front wheel distribution ratio smaller than 1.0. Is calculated.

  Next, the front motor required driving force PFMREQ is calculated by subtracting the front wheel required driving force PFWREQ calculated in step 23 from the provisional value PENREQT of the engine required driving force calculated in step 7, 10 or 11 of FIG. (Step 24). The front motor required driving force PFMREQ is a driving force that needs to be transmitted from the engine 3 to the front motor 4 in order to generate power with the front motor 4 using a part of the engine power. As described above, during the all-wheel drive mode, power is generated by the front motor 4 using a part of the engine power, and the generated power is supplied to the auxiliary machine 8 and the rear motors 41 and 61. The remainder of the engine power is transmitted to the front wheels WFL and WFR. Therefore, the front motor required driving force PFMREQ is calculated by subtracting the front wheel required driving force PFWREQ from the provisional value PENREQT of the engine required driving force as described above.

  In step 25 following step 24, a provisional value EFMOBJT of the front motor target generated power is calculated by searching a predetermined map (not shown) based on the calculated front motor required driving force PFMREQ. The provisional value EFMOBJT of the front motor target generated power is a provisional value of the target value of the front motor generated power, and the driving force transmitted from the engine 3 to the front motor 4 by the execution of step 25 is the front motor required driving force PFMREQ. It is calculated so that.

  Next, the front motor power generation upper limit power FGLMT is calculated by searching a predetermined map (not shown) based on the detected front motor rotation speed NFM (step 26). The front motor power generation upper limit power FGLMT is an upper limit value of power that can be generated by the front motor 4, and is set to a larger value as the front motor rotation speed NMF is higher in the above map. Next, it is determined whether or not the provisional value EFMOBJT of the front motor target generated power calculated in step 25 is larger than the front motor power generation upper limit power FGLMT calculated in step 26 (step 27).

  If the answer to step 27 is NO and EFMOBJT ≦ FGLMT, the provisional value EFMOBJT of the front motor target generated power calculated in step 25 is set as it is as the front motor target generated power EFMOBJ (step 28). Next, a front motor power generation limiting flag F_FMLMT is set to “0” to indicate that the front motor power generation power is not limited to the front motor power generation upper limit power FGLMT (step 29). Next, assuming that the calculation (setting) of the front motor target generated power EFMOBJ is completed, the second completion flag F_DONE2 is set to “1” in order to indicate this (step 30), and this process is terminated.

  On the other hand, if the answer to step 27 is YES and EFMOBJT> FGLMT, the front motor target generated power EFMOBJ is set to the front motor power generation upper limit power FGLMT (step 31). Next, in order to indicate that the front motor power generation power is limited to the front motor power generation upper limit power FGLMT, the front motor power generation limiting flag F_FMLMT is set to “1” (step 32), and the above step 30 is executed. This process is terminated.

  Further, the execution of step 30 results in the answer to step 21 being YES (F_DONE2 = 1). In this case, the steps 22 to 32 are skipped and the process is terminated as it is.

  As described above, according to the present process, the front motor required driving force PFMREQ is calculated by subtracting the front wheel required driving force PFWREQ from the provisional value PENREQT of the engine required driving force (step 24). A provisional value EFMOBJT of the front motor target generated power is calculated based on the front motor required driving force PFMREQ (step 25).

  Further, the front motor target generated power EFMOBJ is limited to the front motor power generation upper limit power FGLMT which is the upper limit value of the power that can be generated by the front motor 4 (steps 27 and 31). Further, when the front motor target generated power EFMOBJ is calculated, the PDU 6 is controlled so that the front motor generated power becomes the front motor target generated power EFMOBJ. As described above, the front motor power generation power is limited to the front motor power generation upper limit power FGLMT or less during the all-wheel drive mode.

  Next, processing for controlling the rear motors 41 and 61 during the all-wheel drive mode will be described with reference to FIG. This process is repeatedly executed at the control cycle, similarly to the processes shown in FIGS. First, in step 41 of FIG. 10, it is determined whether or not the first completion flag F_DONE1 is “1”. When this answer is NO (F_DONE1 = 0), this process is ended as it is.

  On the other hand, when the answer to step 41 is YES (F_DONE1 = 1), that is, when the calculation of the provisional value PENREQT of the engine required driving force is completed, the all-wheel required driving force calculated in step 2 of FIG. Based on PAWREQ, rear wheel required driving force PRWREQ is calculated (step 42). This rear wheel required driving force PRWREQ is a driving force required for the rear motors 41 and 61 to drive the rear wheels WRL and WRR, and is obtained by multiplying the all wheel required driving force PAWREQ by a predetermined rear wheel distribution ratio. Is calculated. The rear wheel distribution ratio is set to a value obtained by subtracting the front wheel distribution ratio from the value 1.0. As described above, the sum of the rear wheel required driving force PRWREQ and the front wheel required driving force PFWREQ calculated in step 23 of FIG. 9 becomes equal to the all wheel required driving force PAWREQ.

  In step 43 following step 42, the rear motor target power ERMOBJ is calculated by searching a predetermined map (not shown) based on the calculated rear wheel required driving force PRWREQ. The rear motor target power ERMOBJ is a target value of power supplied to the rear motors 41 and 61 (hereinafter referred to as “rear motor supply power”), and is transmitted from the rear motors 41 and 61 to the rear wheels WRL and WRR by executing step 43. The driving force is calculated so as to be the rear wheel required driving force PRWREQ.

  Next, it is determined whether or not the calculated rear motor target power ERMOBJ is larger than the rear motor supply upper limit power RELMT (step 44). The rear motor supply upper limit power RELMT is an upper limit value of power that can be supplied from the front motor 4 or the battery 7 to the rear motors 41 and 61, and is calculated by a RELMT calculation process (FIG. 12) described later.

  If the answer to step 44 is YES and ERMOBJ> RELMT, the rear motor target power ERMOBJ is set to the rear motor supply upper limit power RELMT (step 45), and this process ends. On the other hand, when the answer to step 44 is NO, step 45 is skipped and the present process is terminated.

  As described above, according to this process, the rear motor target power ERMOBJ is calculated based on the rear wheel required driving force PRWREQ (step 43) and is limited to the rear motor supply upper limit power RELMT (steps 44 and 45). ). When the rear motor target power ERMOBJ is calculated, the PDU 6 is controlled so that the rear motor supply power (the power supplied to the rear motors 41 and 61) becomes the rear motor target power ERMOBJ. As described above, during the all-wheel drive mode, the rear motor supply power is limited to the rear motor supply upper limit power RELMT or less.

  Further, the relationship between the magnitudes of various parameters such as the all-wheel required driving force PAWREQ described so far is expressed as shown in FIG. 11, for example. This figure shows the case where the rear motor assist control described above is not being executed or the battery charging control is not being executed, the front motor generated power is being restricted, and the rear motor supply power is not being restricted during the all-wheel drive mode. The magnitude relationship between various parameters is schematically shown.

  As shown in FIG. 11, the all-wheel required driving force PAWREQ is equal to the sum of the front wheel required driving force PFWREQ and the rear wheel required driving force PRWREQ, and the provisional value PENREQT of the engine required driving force is the all-wheel required driving force PAWREQ, It is equal to the sum of auxiliary machine required driving force PAC and electric path loss power PEP (step 11). Further, the front motor required driving force PFMREQ is equal to a value obtained by subtracting the front wheel required driving force PFWREQ from the provisional value PENREQT of the engine required driving force (step 24). Further, the upper limit power deviation ΔEFM is equal to a value obtained by subtracting the front motor power generation upper limit power FGLMT from the provisional value EFMOBJT of the front motor target generated power (step 17), and the front motor target power generation power EFMOBJ is equal to the front motor power generation upper limit power FGLMT. Equal (step 31). Further, the engine required driving force PENREQ is equal to the value obtained by subtracting the power deviation correction term COΔEFM from the provisional value PENREQT of the engine required driving force (step 19).

  The provisional value PENREQT of the engine required driving force and the front motor required driving force PFMREQ may be calculated in the following order, for example, without calculating in the order described above. That is, first, the rear wheel required driving force PRWREQ is calculated by multiplying the all wheel required driving force PAWREQ by the rear wheel distribution ratio. Next, the auxiliary required drive power PAC and the electric path loss power PEP are calculated, and the rear motor assist drive power PAS is calculated during the execution of the rear motor assist control, and the required drive power PCH is calculated during the battery charge control. , Respectively. Next, during the execution of the rear motor assist control, the rear motor assist driving force PAS is subtracted from the sum of the calculated rear wheel required driving force PRWREQ, the accessory required driving force PAC, and the electric path loss power PEP. Then, the front motor required driving force PFMREQ is calculated (PFMREQ = PRWREQ + PAC + PEP−PAS).

  Further, during the execution of the battery charging control, the sum of the calculated rear wheel required driving force PRWREQ, accessory required driving force PAC, electric path loss power PEP, and charging required driving force PCH is calculated as the front motor required driving force PFMREQ. (PFMREQ = PRWREQ + PAC + PEP + PCH). Further, when neither the rear motor assist control nor the battery charging control is being executed, the sum of the calculated rear wheel required driving force PRWREQ, the auxiliary required driving force PAC and the electric path loss power PEP is calculated as the front motor. Calculated as the required driving force PFMREQ (PFMREQ = PRWREQ + PAC + PEP).

  Next, the front wheel required driving force PFWREQ is calculated by multiplying the all wheel required driving force PAWREQ by the front wheel distribution ratio. Next, the sum of the calculated front motor required driving force PFMREQ and front wheel required driving force PFWREQ is calculated as a provisional value PENREQT of the engine required driving force (PENREQT = PFMREQ + PFWREQ). Even if the engine required driving force provisional value PENREQT and the front motor requested driving force PFMREQ are calculated in the above order, the engine required driving force provisional value PENREQT, the front motor requested driving force PFMREQ, the all wheel requested driving force PAWREQ, and the front wheel request The relationship among the magnitudes of the driving force PFWREQ, the rear wheel required driving force PRWREQ, the accessory required driving force PAC, and the electric path loss power PEP is exactly the same as the relationship shown in FIG.

  Next, a RELMT calculation process for calculating the rear motor supply upper limit power RELMT will be described with reference to FIG. This process is repeatedly executed at the control cycle, similarly to the processes shown in FIGS. First, in step 51 of FIG. 12, the battery discharge upper limit power EBOLMT is calculated. This battery discharge upper limit electric power EBOLMT is an upper limit value of electric power that can be discharged from the battery 7, and by searching a predetermined map (not shown) based on the calculated state of charge SOC of the battery 7, Calculated. In this map, the battery discharge upper limit power EBOLMT is set to a larger value as the state of charge SOC is larger.

  In steps 52 to 63 following step 51, the rear motor supply upper limit power RELMT is calculated according to the state of charge SOC. First, in step 52, it is determined whether or not the state of charge SOC is equal to or greater than a first predetermined value SOC1. When the answer is YES (SOC ≧ SOC1) and the state of charge SOC is relatively large, the discharge limiting coefficient KDL is set to a value of 1.0 (step 53), and the charging surplus load coefficient KCH is set to a value of 0. (Step 54). This discharge limiting coefficient KDL is used for calculating the rear motor supply upper limit power RELMT in order to limit the power supply from the battery 7 to the rear motors 41 and 61 so as to limit the discharge of the battery 7 in accordance with the state of charge SOC. It is. Further, the charging surplus load coefficient KCH is used to limit the power supply from the front motor 4 to the rear motors 41 and 61 so as to positively charge the battery 7 with the power generated by the front motor 4. It is used for calculation of RELMT.

In step 55 following step 54, the front motor target generated power EFMOBJ calculated in FIG. 9, the battery discharge upper limit power EBOLMT calculated in step 51, the discharge limiting coefficient KDL, and the charging margin load coefficient KCH are calculated. The rear motor supply upper limit power RELMT is calculated by the following equation (4).
RELMT ← EFMOBJ (1-KCH) -EAC + EBOLMT × KDL
...... (4)
Here, the EAC is power supplied to the auxiliary machine 8 (hereinafter referred to as “auxiliary supply power”), and a predetermined map (not shown) is searched based on the above-described auxiliary machine required driving force PAC. Is calculated by

  Next, it is determined whether or not the calculated rear motor supply upper limit power RELMT is smaller than 0 (step 56). If the answer is YES, the rear motor supply upper limit power RELMT is set to 0 (step 57), and this process is terminated. On the other hand, when the answer to step 56 is NO (RELMT ≧ 0), step 57 is skipped and the process is terminated as it is.

  On the other hand, when the answer to step 52 is NO (SOC <SOC1), it is determined whether or not the state of charge SOC is equal to or greater than a second predetermined value SOC2 that is smaller than the first predetermined value SOC1 (step 58). When the answer is YES (SOC1> SOC ≧ SOC2) and the state of charge SOC is slightly small, the discharge limiting coefficient KDL is calculated by searching a predetermined map (not shown) based on the state of charge SOC (step S1). 59), step 54 and the subsequent steps are executed, and this process is terminated.

  In the above map, the discharge limiting coefficient KDL is set to a value smaller than 1.0, and is set to a smaller value as the state of charge SOC is smaller. As shown in the equation (4), the discharge limit coefficient KDL is used as a coefficient to be multiplied by the battery discharge upper limit power EBOLMT in the calculation of the rear motor supply upper limit power RELMT. As described above, the discharge limiting coefficient KDL is set in order to increase the degree of restriction on discharging of the battery 7 by calculating the rear motor supply upper limit power RELMT to a smaller value as the state of charge SOC is smaller. It is.

  On the other hand, when the answer to step 58 is NO (SOC <SOC2), the discharge limiting coefficient KDL is set to 0 (step 60). Next, it is determined whether or not the state of charge SOC is equal to or greater than a third predetermined value SOC3 that is smaller than the second predetermined value SOC2 (step 61). If the answer is YES (SOC2> SOC ≧ SOC3) and the state of charge SOC is relatively small, a charging allowance load coefficient KCH is calculated by searching a predetermined map (not shown) based on the state of charge SOC. (Step 62) and Step 55 and the subsequent steps are executed, and this process is terminated.

  In the above map, the charging margin load coefficient KCH is set to a value smaller than 1.0, and is set to a larger value as the state of charge SOC is smaller. As shown in the equation (4), when the rear motor supply upper limit power RELMT is calculated, a value (1−KCH) obtained by subtracting the charging surplus load coefficient KCH from the value 1 is multiplied by the front motor target generated power EFMOBJ. . As described above, the charging surplus load coefficient KCH is set because the lower the charging state SOC, the lower the motor supply upper limit power RELMT is calculated to a smaller value, so that the electric power generated by the front motor 4 This is because the electric power for charging the battery 7 is increased.

  On the other hand, when the answer to step 61 is NO (SOC <SOC3) and the state of charge SOC is very small, the margin load coefficient KCH for charging is set to a value of 1.0 (step 63) and the steps after step 55 are followed. Execute this to finish this process.

  FIG. 13 illustrates an operation example of the processing illustrated in FIGS. 9, 10, and 12. In the figure, ERMSA (solid line) represents the power supplied to the rear motor, and PRMA (solid line) represents the power of the rear motors 41 and 61 (hereinafter referred to as “rear motor power”). In this operation example, the front motor power generation power is limited to the front motor power generation upper limit power FGLMT (steps 27 and 31 in FIG. 9), so that power is supplied from the battery 7 to the rear motors 41 and 61. Fig. 5 shows an operation when the state of charge SOC is lowered.

  When the state of charge SOC is greater than or equal to the first predetermined value SOC1 (t0 to t1, step 52 in FIG. 12: YES), as described above, the discharge limiting coefficient KDL is set to the value 1.0 (step 53). ) And the charging surplus load coefficient KCH is set to 0 (step 54). Accordingly, the rear motor supply upper limit power RELMT is a value obtained by adding the battery discharge upper limit power EBOLMT to the value obtained by subtracting the auxiliary machine supply power EAC from the front motor target generated power EFMOBJ (= FGLMT) [EFMOBJ (1-0 ) −EAC + EBOLMT × 1.0] (see step 55, equation (4)). In this case, since the front motor target generated power EFMOBJ is limited to the front motor power generation upper limit power FGLMT and is the largest, the rear motor supply upper limit power RELMT (broken line) is maximized.

  In this operation example, the rear motor supply power ERMSA (solid line) that is controlled to be the rear motor target power ERMOBJ is not limited to the rear motor supply upper limit power RELMT, and is smaller than the rear motor supply upper limit power RELMT. . Further, the rear motor power PRMA (solid line) is equal to the rear wheel required driving force PRWREQ (dashed line). In FIG. 13, for easy understanding, the rear wheel required driving force PRWREQ (broken line) is drawn slightly above the rear motor power PRMA (solid line).

  Then, when the state of charge SOC falls below the first predetermined value SOC1 and falls within the range of SOC1> SOC ≧ SOC2 (immediately after time t1 to time t2, step 58 in FIG. 12: YES), the discharge limiting coefficient KDL has the value 1. It is calculated to a value smaller than 0 and smaller as the state of charge SOC becomes smaller (step 59), and the charging margin load coefficient KCH is set to a value 0 (step 54). Accordingly, the rear motor supply upper limit power RELMT is a value obtained by subtracting the above-mentioned auxiliary machine supply power EAC from the front motor target generated power EFMOBJ (= FGLMT), and a value obtained by multiplying the battery discharge upper limit power EBOLMT by the discharge limit coefficient KDL. It is calculated as an added value [EFMOBJ (1-0) −EAC + EBOLMT × KDL]. As a result, rear motor supply upper limit power RELMT decreases as charge state SOC decreases.

  The reduction in the rear motor supply upper limit power RELMT causes the rear motor target power ERMOBJ to reach the rear motor supply upper limit power RELMT, so that the rear motor target power ERMOBJ is set to the rear motor supply upper limit power RELMT (step 45 in FIG. 10). Supply power ERMSA is limited to rear motor supply upper limit power RELMT. As a result, the rear motor power PRMA decreases according to the rear motor supply upper limit power RELMT, and becomes smaller than the rear wheel required driving force PRWREQ. In FIG. 13, the rear motor supply upper limit power RELMT (broken line) is drawn slightly above the rear motor supply power ERMSA (solid line) for easy understanding.

  When the state of charge SOC falls below the second predetermined value SOC2 and falls within the range of SOC2> SOC ≧ SOC3 (immediately after time t2 to time t3, step 61 in FIG. 12: YES), the discharge restriction coefficient KDL becomes zero. With setting (step 60), the charging surplus load coefficient KCH is calculated to a larger value as the charge state SOC is smaller than the value 1.0 and the state of charge SOC is smaller (step 62). Accordingly, the rear motor supply upper limit power RELMT is obtained by subtracting the auxiliary machine supply power EAC from the value obtained by multiplying the front motor target generated power EFMOBJ (= FGLMT) by (1-KCH) [EFMOBJ (1-KCH) − EAC + EBOLMT × 0]. As a result, rear motor supply upper limit power RELMT decreases as charge state SOC decreases. Further, as the rear motor supply upper limit power RELMT decreases, the rear motor supply power ERMSA and the rear motor power PRMA decrease.

  In this case, as is apparent from the calculation method of the rear motor supply upper limit power RELMT, the rear motor supply power ERMSA limited to the rear motor supply upper limit power RELMT is the auxiliary machine supply power from the power generated by the front motor 4 (= EFMOBJ). It becomes smaller by EFMOBJ × KCH than the value obtained by subtracting EAC. As a result, of the electric power generated by the front motor 4, electric power corresponding to EFMOBJ × KCH is charged in the battery 7.

  When the state of charge SOC falls below the third predetermined value SOC3 (immediately after time t3 to immediately before time t4, step 61 in FIG. 12: NO), the discharge restriction coefficient KDL is set to a value 0 (step 60), and charging is performed. The marginal load factor KCH is set to a value of 1.0 (step 63). Correspondingly, the rear motor supply upper limit power RELMT calculated by the equation (4) becomes a negative value, so that the value of 0 is set by the execution of steps 56 and 57. As a result, power supply from the front motor 4 to the rear motors 41 and 61 is stopped (prohibited), so that the rear motor supply power ERMSA and the rear motor power PRMA become zero. As a result, the electric power for EFMOBJ-EAC is charged in the battery 7, and then the state of charge SOC increases.

  When the state of charge SOC becomes equal to or higher than the third predetermined value SOC3 (after time t4) due to charging of the battery 7 using the electric power generated by the front motor 4, the above-described operation is repeated accordingly. The reason why the auxiliary machine supply power EAC is used as a subtraction term in the above equation (4) is to reliably supply a part of the power generated by the front motor 4 to the auxiliary machine 8.

The correspondence between various elements in the present embodiment and various elements in the present invention is as follows. That is, the front motor 4, the rear motors 41 and 61, and the battery 7 in the present embodiment correspond to the first motor, the second motor, and the battery in the present invention, respectively, and the rear wheels WRL and WRR in the present embodiment correspond to the present invention. It corresponds to the wheel. Further, the front wheels WFL and WFR in the present embodiment correspond to other wheels in the present invention, and the ECU 2 in the present embodiment includes a wheel required driving force calculating means, an internal combustion engine control means, a first motor control means in the present invention, The PDU 6 in the present embodiment corresponds to the first motor control means, the second motor control means, and the restriction means in the present invention as well as the second motor control means and the restriction means.

  As described above, according to this embodiment, during the all-wheel drive mode, basically, a part of the engine power is transmitted to the rear wheels WRL and WRR via the front motor 4 and the rear motors 41 and 61. In addition, the remaining engine power is transmitted to the front wheels WFL and WFR. In this case, the all-wheel required driving force PAWREQ, which is the driving force required to drive the entire front wheels WFL, WFR and the rear wheels WRL, WRR, is calculated (step 2 in FIG. 7), and the engine power is Control is performed according to the all-wheel required driving force PAWREQ (steps 7, 10, 11 and step 15 in FIG. 8). As described above, the all-wheel required driving force PAWREQ includes the rear wheel required driving force PRWREQ that is a driving force required to drive the rear wheels WRL and WRR.

  Further, in order to supply the electric power generated by the front motor 4 to the rear motors 41 and 61, the power generation by the front motor 4 using a part of the engine power is basically controlled based on the front motor required driving force PFMREQ. (Steps 25 and 28 in FIG. 9). The front motor required driving force PFMREQ is calculated by subtracting the front wheel required driving force PFWREQ, which is the driving force required for driving the front wheels WFL, WFR, from the provisional value PENREQT of the engine required driving force (step). 24). The provisional value PENREQT of the engine required driving force is calculated by adding or subtracting parameters such as the auxiliary device required driving force PAC to the all-wheel required driving force PAWREQ (steps 7, 10, 11). Further, the value obtained by subtracting the front wheel required driving force PFWREQ from the all wheel required driving force PAWREQ is equal to the rear wheel required driving force PRWREQ. As is clear from the above, the power generation by the front motor 4 is basically controlled according to the rear wheel required driving force PRWREQ.

  During the all-wheel drive mode, the driving force transmitted from the engine 3 to the front wheels WFL and WFR is appropriately controlled according to the front wheel required driving force PFWREQ by controlling the engine power and the power generation of the front motor 4 described above. Can do.

  Further, during the all-wheel drive mode, the rear motor supply power is basically controlled based on the rear wheel required drive power PRWREQ (step 43 in FIG. 10). The driving force transmitted from the engine 3 to the rear wheels WRL and WRR via the front motor 4 and the rear motors 41 and 61 by the control of the power supplied to the rear motor and the control of the engine power and the power generation of the front motor 4 described above. Can be appropriately controlled based on the rear wheel required driving force PRWREQ. As described above, the driving force transmitted to the entire front wheels WFL, WFR and the rear wheels WRL, WRR can be appropriately controlled according to the all-wheel required driving force PAWREQ.

  Further, during the all-wheel drive mode, the front motor power generation power is limited to the front motor power generation upper limit power FGLMT (steps 27 and 31 in FIG. 9), so that it is possible to prevent the front motor power generation power from being excessively increased. 4 lifespan can be extended. Further, during the all-wheel drive mode, when the front motor power generation power is limited to the front motor power generation upper limit power FGLMT (step 14 in FIG. 8: YES), the engine power further depends on the limited front motor power generation power. Are controlled (steps 17 to 19).

  Specifically, the upper limit power deviation ΔEFM is calculated by subtracting the front motor power generation upper limit power FGLMT from the provisional value EFMOBJT of the front motor target generated power, and the calculated upper limit power deviation ΔEFM is converted into power. The engine required driving force PENREQ is subtracted by the correction term COΔEFM. As a result, the engine power is controlled to a value obtained by subtracting the power deviation correction term COΔEFM from the sum of the all-wheel required driving force PAWREQ and the parameters such as the auxiliary device required driving force PAC. In this way, the engine power is reduced according to the limited front motor power generation, so that it is not necessary to generate waste. For the same reason, it is possible to appropriately control the driving force transmitted from the engine 3 to the front wheels WFL and WFR according to the front wheel required driving force PFWREQ without increasing the driving force with the restriction of the front motor generated power.

  Further, during the all-wheel drive mode, when the front motor power generation power is limited to the front motor power generation upper limit power FGLMT, the power supplied from the front motor 4 to the rear motors 41 and 61 and the auxiliary machine 8 is the upper limit power deviation ΔEFM. Decrease by minute. According to this embodiment, when the front motor power generation power is limited to the front motor power generation upper limit power FGLMT, the rear motor target power ERMOBJ based on the rear wheel required driving force PRWREQ is used for controlling the rear motor supply power. The rear motor supply power is controlled so that the power corresponding to the upper limit power deviation ΔEFM is supplemented by the power of the battery 7 (step 43 in FIG. 10).

  Accordingly, since the rear motor supply power can be appropriately controlled based on the rear wheel required driving force PRWREQ while the front motor generated power is limited, the driving force transmitted from the rear motors 41 and 61 to the rear wheels WRL and WRR can be controlled. Can be controlled appropriately. As described above, while the front motor generated power is limited, the driving force transmitted from the engine 3 to the front wheels WFL and WFR can be appropriately controlled according to the front wheel required driving force PFWREQ, and the rear motors 41 and 61 Since the driving force transmitted to the wheels WRL and WRR can be appropriately controlled based on the rear wheel required driving force PRWREQ, drivability can be improved.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the battery in the present invention is the battery 7, but may be a capacitor. In the embodiment, the first and second rear motors 41 and 61 are connected to the left and right rear wheels WRL and WRR via the first and second planetary gear devices 51 and 71, respectively. It may be connected directly to the left and right rear wheels WRL, WRR without going through 71. Furthermore, in the embodiment, the engine 3 and the front motor 4 are connected to the front wheels WFL and WFR via a transmission 5 configured by a dual clutch transmission. However, the engine 3 and the front motor 4 are connected via another appropriate transmission. Also good.

  In the embodiment, the engine 3 and the front motor 4 corresponding to the internal combustion engine and the first electric motor in the present invention are connected to the front wheels WFL and WFR, and the rear motors 41 and 61 corresponding to the second electric motor in the present invention are connected to the rear wheels. Although connected to WRL and WRR, on the contrary, the internal combustion engine and the first electric motor may be connected to the rear wheel and the second electric motor may be connected to the front wheel. Furthermore, in the embodiment, two motors including the first and second rear motors 41 and 61 are used as the second electric motor in the present invention, but a single motor may be used.

  The embodiment is an example in which the present invention is applied to the hybrid vehicle V in which the auxiliary machine 8 is connected to the front motor 4, the rear motors 41 and 61, and the battery 7, but the present invention is connected to the auxiliary machine. It is also applicable to other types of hybrid vehicles. In this case, the parameters (PAC, EAC) related to the auxiliary machine are deleted in the above-described processing (FIGS. 7 to 10 and 12). Furthermore, in the embodiment, the internal combustion engine in the present invention is the engine 3 that is a gasoline engine, but may be a diesel engine, an LPG engine, or the like. Further, in the embodiment, the number of front wheels WFL and WFR and the number of rear wheels WRL and WRR of the hybrid vehicle V are two, but the number is not limited to this. One of the numbers may be one and the other may be two, or three or more each.

  Further, the embodiment is an example in which the present invention is applied to the hybrid vehicle V in which the engine 3 and the front motor 4 are connected to the front wheels WFL and WFR. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention can also be applied to a so-called series type hybrid vehicle in which an electric motor is not connected to a wheel. In the embodiment, various parameters such as the all-wheel required driving force PAWREQ and the rear wheel required driving force PRWREQ are calculated as power, but may be calculated as torque and output correlated with the driving force. Furthermore, it goes without saying that variations of the above embodiments may be combined as appropriate. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

V hybrid vehicle
WFL Front left wheel (other wheels)
WFR Right front wheel (other wheels)
WRL Left rear wheel (wheel)
WRR Right rear wheel (wheel)
1 Control device
2 ECU (Wheel required driving force calculation means, internal combustion engine control means, first motor control means, second motor control means, restriction means)
3 Engine
4 Front motor (first motor)
6 PDU (first motor control means, second motor control means, limiting means)
7 Battery (capacitor)
41 First rear motor (second electric motor)
61 Second rear motor (second electric motor)
PFWREQ Front wheel required driving force (second wheel required driving force)
PRWREQ Required rear wheel driving force ( 1st wheel required driving force )
FGLMT Front motor power generation upper limit power (upper limit)

Claims (1)

An internal combustion engine as a power source, a first electric motor mechanically connected to the internal combustion engine, a second electric motor mechanically connected to the wheel to drive the wheels, and the first and second electric motors A control device for a hybrid vehicle including an electrically connected battery,
The internal combustion engine is mechanically coupled to the other wheel to drive another wheel different from the wheel;
Wheel required driving force calculating means for calculating a first wheel required driving force required for driving the wheel and a second wheel required driving force required for driving the other wheel;
Internal combustion engine control means for controlling the power of the internal combustion engine in accordance with the calculated first and second wheel required driving forces;
A first motor that controls power generation by the first motor using the power of the internal combustion engine according to the first wheel required driving force in order to supply electric power generated by the first motor to the second motor. Control means;
Second motor control means for controlling second motor supply power, which is power supplied to the second motor, based on the first wheel required driving force;
Limiting means for limiting the first motor generated power, which is the power generated by the first motor by the control of the first motor control means, to be equal to or lower than the upper limit value of the power that can be generated by the first motor, Prepared,
The internal combustion engine control means when said first motor generator power is limited to less than the upper limit value by the limiting means, minutes of the first motor generated power is reduced by the limit, the power of the internal combustion engine The first and second wheels are controlled so as to be reduced as compared with the case where the control is performed according to the required driving force ,
The second motor control means, when said first electric motor generated power by the limiting means is limited to less than the upper limit value, based on said first wheel required driving force, the by the restriction by the restricting means A control apparatus for a hybrid vehicle, wherein the second electric motor supply electric power is controlled such that electric power corresponding to a decrease in electric power generated by the first electric motor is supplemented by electric power of the battery.

Images