JP5206435B2 - Vehicle driving force control device and driving force control method - Google Patents

Description

  The present invention provides a generator for transmitting a driving torque of a main driving source to a main driving wheel via a transmission having a torque converter with a lock-up clutch and supplying electric power to a motor capable of driving the driven wheel. The present invention relates to a driving force control technique for a vehicle driven by the main drive source.

  As a vehicle driving force control device, for example, there is a device described in Patent Document 1. That is, the drive torque of the main drive source is transmitted to the main drive wheels via the automatic transmission. Further, the electric power of the generator driven by the main drive source is supplied to the motor, and the driven wheels can be driven by the drive torque of the motor. When the driven wheels are driven with the power generated by the generator, the shift schedule of the automatic transmission is prohibited from being changed. This eliminates the power generation shortage of the generator.

JP 2004-100718 A

Here, the automatic transmission generally includes a lock-up clutch that directly connects the torque converter. The lock-up clutch is preferably engaged as soon as possible from the viewpoint of improving fuel efficiency. In the case of a continuously variable transmission, it can be locked up from a low vehicle speed range as compared with a stepped automatic transmission (stepped AT).
However, when locking up while driving the driven wheels with the power generated by the generator, it may be difficult to generate the target power with the generator.
This invention pays attention to the above points, and makes it a subject to optimize the electric power generation amount of the generator at the time of a motor drive.

  The present invention has been made paying attention to the above points, and the present invention transmits the drive torque of the main drive source to the main drive wheels via a transmission including a torque converter with a lock-up clutch. Moreover, it is set as the structure which can drive a driven wheel by the motor driven with the electric power of the generator driven with the said main drive source. And in the motor drive state which drives the motor with the electric power of a generator, the fastening state of the said lockup clutch is prohibited.

  According to the present invention, lockup is prohibited in a motor drive state in which a drive torque is generated with respect to the driven wheels by the motor. This reliably prevents a decrease in the rotation speed of the main drive source due to the lockup, and suppresses a decrease in the rotation speed for generating the generator. As a result, the possibility of securing the power generation amount of the generator when driving the motor to an appropriate value increases. That is, it is possible to optimize the power generation amount of the generator.

It is a schematic device configuration diagram of a vehicle according to an embodiment based on the present invention. It is a block diagram of the control system which concerns on embodiment based on this invention. It is a functional block diagram which shows the 4WD controller which concerns on embodiment based on this invention. It is a flowchart which shows the control processing procedure in the 4WD controller which concerns on embodiment based on this invention. It is a flowchart which shows an example of the process sequence of the surplus torque calculating part which concerns on embodiment based on this invention. It is a flowchart which shows an example of the process sequence of the target torque control part which concerns on embodiment based on this invention. It is a figure which shows the engine torque calculation map which shows the relationship between throttle opening (theta) and engine torque Te by using engine speed Ne as a parameter. It is a flowchart which shows an example of the process sequence of the surplus torque conversion part which concerns on embodiment based on this invention. It is a figure which shows the armature current target value calculation map which shows the relationship between a motor torque target value and an armature current target value by using a motor field current target value as a parameter. It is a flowchart which shows an example of the process sequence of the transmission control part which concerns on embodiment based on this invention. It is a figure which shows the relationship between a minimum rotation speed and throttle opening. It is an example of a shift schedule. It is a flowchart which shows an example of the process sequence of a transmission controller. It is a figure explaining the restriction | limiting of the fall of an engine speed. It is a figure of the example of a time chart which concerns on embodiment based on this invention. It is a flowchart which shows an example of the process sequence of the transmission control part which concerns on embodiment based on this invention. It is an example of the shift schedule of CVT.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment when the present invention is applied to a four-wheel drive vehicle.
(Constitution)
The engine 2 which is an internal combustion engine drives the left and right front wheels 1FL and 1FR as main drive wheels. The left and right rear wheels 1RL and 1RR as the driven wheels can be driven by the motor 3 which is an electric motor.

An automatic transmission 4 having a torque converter with a lockup clutch is interposed in the middle of the torque transmission path from the engine 2 to the left and right front wheels 1FL, 1FR. That is, the output torque Te of the engine 2 can be transmitted to the left and right front wheels 1FL and 1FR via the automatic transmission 4 and the differential gear 5 having a torque converter with a lockup clutch.
The automatic transmission 4 changes the shift position to a shift position according to a command from a transmission controller 41 described later. Also, when a lockup command is input, the lockup clutch is engaged, and when a lockup release command is input, a lockup release command is output.

A part of the output torque Te of the engine 2 can be transmitted to the generator 7 through the endless belt 6.
The generator 7 rotates at a rotational speed Ng obtained by multiplying the rotational speed Ne of the engine 2 by the pulley ratio. Then, the generator 7 becomes a load on the engine 2 according to the field current Ifg adjusted by the 4WD controller 8, and generates electric power according to the load torque. The electric power generated by the generator 7 can be supplied to the motor 3 via the electric wire 9 and the junction box 10. The output shaft of the motor 3 is connected to the speed reducer 11, the clutch 12, and the differential gear 13. The left and right output sides of the differential gear 13 are connected to the left and right rear wheels 1RL and 1RR via the drive shafts 13L and 13R, respectively.

  A main throttle valve 15 and a sub-throttle valve 16 are interposed in the intake pipe 14 (for example, intake manifold) of the engine 2. The throttle opening of the main throttle valve 15 is adjusted and controlled according to the depression amount of the accelerator pedal 17 and the like. The main throttle valve 15 is mechanically linked to the depression amount of the accelerator pedal 17, or the engine controller 19 is electrically operated according to the depression amount detection value of the accelerator sensor 18 that detects the depression amount of the accelerator pedal 17. By performing adjustment control, the throttle opening is adjusted. The detected amount of depression of the accelerator sensor 18 is also output to the 4WD controller 8.

  The sub-throttle valve 16 is adjusted and controlled by a rotation angle corresponding to the number of steps using the step motor 20 as an actuator. The rotation angle of the step motor 20 is adjusted and controlled by a drive signal from the motor controller 21. The sub throttle valve 16 is provided with a throttle sensor 22. Based on the throttle opening detection value detected by the throttle sensor 22, the number of steps of the step motor 20 is feedback controlled. Here, by adjusting the throttle opening degree of the sub throttle valve 16 to be equal to or less than the opening degree of the main throttle valve 15, the output torque of the engine 2 is reduced independently of the driver's operation of the accelerator pedal. Can do.

  Further, the engine 2 is provided with an engine rotation speed sensor 23 for detecting the output rotation speed Ne. The engine speed Ne detected by the engine speed sensor 23 is output to the 4WD controller 8. Furthermore, wheel speed sensors 24FL to 24RR for detecting the wheel speed are provided for the respective wheels 1FL to 1RR. The wheel speeds VwFL to VwRR detected by these wheel speed sensors 24FL to 24RR are output to the 4WD controller 8. Furthermore, a shift position sensor 25 for detecting the shift position of the automatic transmission 4 and a torque sensor 26 for detecting the front-wheel drive torque on the output side of the automatic transmission 4 are provided. The shift position detected by the shift position sensor 25 and the front wheel drive torque TF detected by the torque sensor 26 are input to the 4WD controller 8. Furthermore, a 4WD switch 26 is provided in the vicinity of the driver's seat to select whether or not to set the four-wheel drive state, and the switch signal of the 4WD switch 27 is output to the 4WD controller 8.

  Further, the generator 7 includes a delta-connected three-phase stator coil SC and a field coil FC as shown in FIG. Each connection point of the stator coil SC is connected to a rectifier circuit 30 formed of a diode, and a DC voltage VG of, for example, 42 V at maximum is output from the rectifier circuit 30. In addition, one end of the field coil FC is connected to the output side of the rectifier circuit 30 through the diode D1, and the diode D2 is connected in the reverse direction, and further, a predetermined voltage (for example, 12 volts) is supplied through the 4WD relay 31. Connect to battery 32. Further, the other end of the field coil FC is connected to the cathode side of the diodes D1 and D2 via the flywheel diode DF in the forward direction, and is grounded via a bipolar transistor 33 constituting a voltage regulator (regulator). Yes.

Here, a system that supplies the field current Ifg via the rectifier circuit 30 and the diode D1 forms a self-excited circuit. A system that supplies the field current Ifg via the battery 31 and the diode D2 forms a separate excitation circuit. The diodes D1 and D2 have a select high function for selecting the higher one of the voltages of the self-excited circuit and the separately-excited circuit.
One end of the relay coil of the 4WD relay 31 is connected to the output side of an ignition relay 35 connected to the battery 32 via an ignition switch 34. The other end of the relay coil of the 4WD relay 31 is connected to the 4WD controller 8.

  The generator 7 adjusts the field current Ifg with respect to the field coil FC by the 4WD controller 8, thereby controlling the power generation load torque Tg for the engine 2 and the generated power generation voltage VG. The bipolar transistor 33 receives a generator control command (field current value) C1 subjected to pulse width modulation (PWM) from the 4WD controller 8 and sets the field current Ifg of the generator 7 to a value corresponding to the generator control command C1. Adjust.

  In addition, a motor relay 36 and a current sensor 37 are provided in the junction box 10 in series. The motor relay 36 interrupts the power supplied to the motor 3 according to a command from the 4WD controller 8. The current sensor 37 detects the armature current Ia supplied from the generator 7 to the motor 3 and outputs the detected armature current Ia to the 4WD controller 8. Further, the 4WD controller 8 acquires the motor voltage Vm supplied to the motor 3.

  Further, the field current Ifm of the motor 3 is controlled by a pulse width modulated field control command as a motor output torque command from the 4WD controller 8. The drive torque Tm of the motor 3 is adjusted by adjusting the field current Ifm. The thermistor 38 detects the temperature of the motor 3 and outputs the detected temperature value to the 4WD controller 8. A motor rotation speed sensor 39 as a motor rotation speed detection means detects the rotation speed Nm of the output shaft of the motor 3 and outputs the rotation speed Nm to the 4WD controller 8.

  The electromagnetic clutch 12 has one end of the exciting coil 12 a connected to the output side of the 4WD relay 21. The other end of the exciting coil 12 a is connected to the 4WD controller 8. The exciting coil 12a is grounded via a switching transistor 40 as a switching element in the 4WD controller 8. Then, the energization current of the exciting coil 12a is controlled by the pulse width modulated clutch control command CL supplied to the base of the transistor 40. As a result, the torque transmission force transmitted from the motor 3 to the rear wheels 1RL and 1RR as the driven wheels is controlled.

As shown in FIG. 3, the 4WD controller 8 includes a generator control unit 8A, a relay control unit 8B, a motor control unit 8C, a clutch control unit 8D, a surplus torque calculation unit 8E, a target torque limiting unit 8F, and a surplus torque conversion unit 8G. And a shift control unit 8T.
The generator control unit 8A adjusts the field current Ifg of the generator 7 while monitoring the generated voltage V of the generator 7 through the bipolar transistor 33. Thus, the generator control unit 8A adjusts the generated voltage VG of the generator 7 to a required voltage.
The relay control unit 8 </ b> B controls interruption / connection of power supply from the generator 7 to the motor 3.
The motor control unit 8C adjusts the field current Ifm of the motor 3 based on the target motor field current Ifmt calculated by the surplus torque conversion unit 8G described later. As a result, the motor control unit 8C adjusts the torque of the motor 3 to a required value.

The clutch control unit 8D calculates the corresponding motor torque target value Tmt based on the power generation load torque target value Tgt calculated by the surplus torque calculation unit 8E described later. Based on the motor torque target value Tmt, the following formula is calculated to calculate the clutch transmission torque TCL for the electromagnetic clutch 12. This clutch transmission torque TCL is converted into a clutch current command value ICL, and this is subjected to pulse width modulation (PWM) to obtain a clutch current control output CL having a duty ratio corresponding to the clutch current command value ICL. Output.
TCL = Tmt x KDEF x KTM + TCL0
Here, KDEF is a reduction ratio in the differential gear 13, KTM is a clutch torque margin, and TCL0 is a clutch initial torque.
Further, as shown in FIG. 4, the processing is executed by circulating in the order of the surplus torque calculation unit 8E → the target torque limiting unit 8F → the surplus torque conversion unit 8G based on each input signal at every predetermined sampling time.

First, the surplus torque calculation unit 8E performs processing as shown in FIG.
That is, first, in step S1, a slip speed ΔVF that is an acceleration slip amount of the front wheels 1FL, 1FR is obtained based on signals from the wheel speed sensors 16FL, 16FR, 16RL, 16RR. That is, by subtracting the average wheel speed VWr of the rear wheels 1RL, 1RR (secondary drive wheels) from the average wheel speed VWf of the front wheels (main drive wheels) 1FL, 1FR, a slip speed that is an acceleration slip amount of the front wheels 1FL, 1FR. ΔVF is obtained.
The calculation of the slip speed ΔVF is performed as follows, for example.
The average front wheel speed VWf and the average rear wheel speed VWr are respectively calculated by the following equations.
VWf = (VWFL + VWFR) / 2 (1)
VWr = (VWRL + VWRR) / 2 (2)

Next, from the deviation between the average front wheel speed VWf and the average rear wheel speed VWr, the slip speed (acceleration slip amount) ΔVF of the front wheels 1L and 1R, which are the main drive wheels, is calculated by the following equation (3).
ΔVF = VWf−VWr (3)
Next, the process proceeds to step S2, and it is determined whether or not the slip speed ΔVF obtained in step S1 is a positive value greater than a predetermined value, for example, “0”. When the determination result indicates that the slip speed ΔVF is equal to or lower than “0”, that is, “0” or a negative value, it is estimated that the front wheels 1FL and 1FR are not accelerating and slipping, and the process proceeds to step S3. In step S3, the post-processing is completed after setting the power generation load torque target value Tgt to “0”, and the process proceeds to the processing of the target torque limiting unit 8F.

On the other hand, when the slip speed ΔVF is a positive value larger than “0” in step S2, it can be estimated that the front wheels 1FL and 1FR are slipping at an acceleration, and therefore the process proceeds to step S4.
In this step S4, the absorption torque TΔVF necessary for suppressing the acceleration slip of the front wheels 1FL, 1FR is calculated by the following equation (4), and thereafter, the process proceeds to step S5. The absorption torque TΔVF is an amount proportional to the acceleration slip amount.
TΔVF = K1 × ΔVF (4)
Here, K1 is a gain obtained through experiments or the like.

In step S5, the current load torque TG of the generator 7 is calculated based on the following equation (5), and then the process proceeds to step S6.
Vg x Ia
TG = K2 ・ ───── (5)
K3 x Ng
Here, Vg is the voltage of the generator 7, Ia is the armature current of the generator 7, Ng is the rotational speed of the generator 7, K2 is a coefficient, and K3 is the efficiency.
In step S6, after determining the surplus torque, that is, the power generation load torque target value Tgt to be loaded by the generator 7, based on the following equation (6), the process is terminated and the process proceeds to the process of the target torque limiting unit 8F.
Tgt = TG + TΔVF (6)

Next, the processing of the target torque limiting unit 8F will be described based on FIG.
That is, first, in step S11, it is determined whether the power generation load torque target value Tgt is greater than the maximum load capacity HQ of the generator 7. When it is determined that the power generation load torque target value Tgt is equal to or less than the maximum load capacity HQ of the generator 7, the process is terminated. On the other hand, when it determines with the electric power generation load torque target value Tgt being larger than the maximum load capacity HQ of the generator 7, it transfers to step S12.

In step S12, an excess torque ΔTb exceeding the maximum load capacity HQ at the power generation load torque target value Tgt is obtained by the following equation (7). Thereafter, the process proceeds to step S13.
ΔTb = Tgt−HQ (7)
In step S13, the current engine torque Te is calculated based on the signals from the throttle sensor 22 and the engine rotation speed sensor 23 with reference to the engine torque calculation map shown in FIG. Thereafter, the process proceeds to step S14.

In step S14, as shown in the following equation (8), the engine torque upper limit value TeM is calculated by subtracting the excess torque ΔTb from the engine torque Te. After the obtained engine torque upper limit value TeM is output to the engine controller 19, the process proceeds to step S15.
TeM = Te−ΔTb (8)
Here, the engine controller 19 limits the engine torque Te so that the input engine torque upper limit TeM becomes the upper limit value of the engine torque Te regardless of the driver's operation of the accelerator pedal 17.
In step S15, the process ends after setting the maximum load capacity HQ to the power generation load torque target value Tgt, and the process proceeds to the process of the surplus torque converter 8G.

Next, the process of the surplus torque converter 8G will be described based on FIG.
First, in step S20, it is determined whether or not the slip speed ΔVF is greater than “0”. When this determination result is ΔVF ≦ 0, it is determined that no acceleration slip has occurred, and the process proceeds to step S21.
In step S21, it is determined whether or not the operation flag F4WD indicating whether or not the four-wheel drive state is set by driving the electric motor 3 is reset to "0". When the operation flag F4WD is reset to “0”, the process is terminated without performing the surplus torque conversion process, and the process returns to the process of the surplus torque calculation unit 8E. On the other hand, when the operation flag F4WD is set to "1", the process proceeds to step S23 described later.

On the other hand, when the determination result in step S20 is ΔVF> 0, it is determined that the front wheels 1FL and 1FR are slipping at acceleration, and the process proceeds to step S22.
In step S22, the rotational speed Nm of the motor 3 detected by the motor rotational speed sensor 39 is input. Based on the rotational speed Nm of the motor 3, the motor field current target value Ifmt is calculated with reference to the motor field current target value calculation map shown in FIG.

  Here, the target motor field current calculation map is created on the basis of the speed ratio of the first speed at which the automatic transmission 4 becomes the maximum speed ratio in the drive (D) range. Here, in FIG. 8, the horizontal axis represents the motor rotation speed Nm, and the vertical axis represents the motor field current target value Ifmt. The characteristic line L1 is set as follows. That is. When the motor rotational speed Nm is between "0" and the first set value N1, the motor field current target value Ifmt maintains the preset maximum current value IMAX. When the motor rotational speed Nm increases beyond the first set value N1, the motor field current target value Ifmt decreases accordingly with a relatively large gradient. The motor field current target value Ifmt is the initial current during the period from the second set value N2 where the motor rotational speed Nm is greater than the first set value N1 to the third set value N3 which is greater than the second set value N2. A low current value IL smaller than the value IIN is maintained. When the motor rotation speed Nm increases beyond the third set value N3, the motor field current target value Ifmt decreases correspondingly and becomes “0”.

  That is, a constant predetermined current value IMAX is set when the rotational speed Nm is between "0" and the set value N1. When the motor 3 reaches the rotational speed set value N1 or more, the field current Ifm of the motor 3 is reduced by a known field weakening control method. That is, when the motor 3 is rotated at a high speed, the motor torque is reduced due to an increase in the induced voltage in the motor 3, and as described above, when the rotational speed Nm of the motor 3 exceeds a predetermined value N1, the field current of the motor 3 is increased. Ifm is reduced. As a result, by reducing the induced voltage E, the current flowing through the motor 3 is increased and the required motor torque Tm is obtained. As a result, even if the motor 3 rotates at a high speed, the increase in the motor induced voltage E is suppressed and the decrease in the motor torque is suppressed. Therefore, the required motor torque Tm can be obtained. In addition, by controlling the motor field current Ifm in two stages of less than a predetermined rotation speed and more than a predetermined rotation speed, the electronic control circuit can be configured at a lower cost than continuous field current control.

Next, the process proceeds to step S24, the motor field current target value Ifmt calculated in step S23 is output to the motor control unit 8C, and the process proceeds to step S25.
In step S25, the motor induced voltage E is determined by referring to the motor induced voltage calculation map shown in FIG. 8 based on the motor rotation speed Nm and the motor field current target value Ifmt calculated in step S23. calculate. Here, the motor induced voltage calculation map uses the motor field current target value Ifmt as a parameter, the horizontal axis represents the motor rotation speed Nm, and the vertical axis represents the motor induced voltage E. The motor induced voltage E is linearly increased by increasing the motor rotation speed Nm, and the motor induced voltage E is also increased by increasing the motor field current target value Ifmt.

Next, the process proceeds to step S26, and it is determined whether or not the four-wheel drive end condition is satisfied. This determination is performed, for example, by determining whether or not the previous motor torque target value Tmt (n-1) is equal to or less than a preset motor torque threshold value TmTH. When Tmt (n-1)> TmTH, it is determined that the four-wheel drive end condition is not satisfied, and the process proceeds to step S27. When Tmt (n−1) ≦ TmTH, it is determined that the four-wheel drive end condition is satisfied, and the routine goes to Step S30.
In step S27, the corresponding motor torque target value Tmt is calculated based on the power generation load torque target value Tgt calculated by the surplus torque calculator 8E, and the process proceeds to step S28.

  In step S28, the electronic current target value Iat is calculated with reference to the armature current target value calculation map shown in FIG. 9 based on the motor torque target value Tmt and the motor field current target value Ifmt. This armature current target value calculation map uses the motor field current target value Ifmt as a parameter, the motor torque target value Tmt on the horizontal axis, and the armature current target value Iat on the vertical axis. When the motor output torque Tm is “0”, the armature current target value Iat is “0” regardless of the value of the motor field current target value Ifmt. From this state, the armature current target value Iat increases as the motor output torque Tm increases, and the armature current target value Iat decreases as the motor field current target value Ifmt increases. When the motor output torque Tm becomes a large value, the armature current target value Iat is set to “0” sequentially from the smaller motor field current target value Ifmt.

Subsequently, the process proceeds to step S29, and the voltage target of the generator 7 is determined from the armature current target value Iat, the combined resistance R of the resistance of the electric wire 9 and the resistance of the coil of the motor 3, and the induced voltage E based on the following equation (9). The value VG is calculated. After the voltage target value VG of the generator 7 is output to the generator control unit 8A, the process ends and the process returns to the surplus torque calculation unit 8E.
V G = Iat × R + E (9)

On the other hand, in step S30, a motor torque reduction process is performed. That is, a value obtained by subtracting the predetermined decrease amount ΔTmt from the previous motor torque target value Tmt (n−1) is calculated as the current motor torque target value Tmt (n) (= Tmt (n−1) −ΔTmt). Thereafter, the process proceeds to step S31.
In step S31, it is determined whether or not the motor torque target value Tmt (n) is equal to or less than “0”. When Tmt (n)> 0, the process proceeds to step S28. On the other hand, when Tmt (n) .ltoreq.0, the routine proceeds to step S32, where the operation flag F4WD is reset to "0" and the processing is terminated.

Next, the processing of the shift control unit 8T will be described with reference to FIG.
The shift control unit 8T operates every predetermined sampling period.
First, in step S100, it is determined whether or not the 4WD state is set. In the 4WD state, the process proceeds to step S110. On the other hand, if it is not in the 4WD state, that is, in the 2WD state, the process proceeds to step S140.
Here, the 4WD state is a motor drive state, and in this embodiment, determination can be made based on whether ΔVF> 0.
In step S110, the lockup prohibition flag LUOFF is turned ON, and the process proceeds to step S120.
In step S120, the 4WD shift line flag TIS4FLG is turned ON, and the process proceeds to step S130.
In step S130, the 4WD state flag T4FLG is turned on and then returned.

On the other hand, in the 2WD state, the process proceeds to step S140, the lockup prohibition flag LUOFF is turned OFF, and the process proceeds to step S150.
In step S150, it is determined whether the 4WD state flag T4FLG is ON. That is, it is determined whether or not it is a transition period from the 4WD state to the 2WD state. When the 4WD state flag T4FLG is ON, the process proceeds to step S160. If the 4WD state flag T4FLG is OFF, the process returns as it is. When the 4WD state flag T4FLG is OFF, the 4WD shift line flag TIS4FLG is OFF, the lockup prohibition flag LUOFF is OFF, and the shift holding flag TKeep is OFF.

In step S160, after obtaining the lower limit target rotational speed based on the throttle opening TVO based on the map as shown in FIG. 11, the process proceeds to step S170. As shown in FIG. 11, the lower limit target rotational speed LimΔN increases as the throttle opening TVO decreases.
In step S170, the 4WD shift line flag TIS4FLG is turned OFF and the process proceeds to step S180.

In step S180, it is determined whether or not the actual decrease in engine speed is greater than the lower limit target speed LimΔN. If the actual drop is larger than the lower limit target rotational speed LimΔN, the process proceeds to step S190. If the actual drop is less than or equal to the lower limit target rotational speed LimΔN, the process proceeds to step S200.
The actual drop is a drop amount of “the current engine speed” from “the engine speed when the 4WD state is switched to the 2WD state”.
In step S190, the shift holding flag TKeep is turned on to return.
On the other hand, in step S200, the shift holding flag TKeep is turned off. Subsequently, in step S210, the 4WD state flag T4FLG is turned OFF to return.

Next, processing of the transmission controller 41 will be described.
The transmission controller 41 refers to a shift schedule (shift diagram) as shown in FIG. 12, determines the shift position based on the accelerator opening (or throttle valve opening) and the vehicle speed, and issues a shift command corresponding thereto. Output to the transmission 4. Also, referring to the shift schedule (shift diagram), if it is determined that the vehicle speed is greater than or equal to a predetermined vehicle speed based on the accelerator opening (or throttle valve opening) and the vehicle speed, a lockup command is output to the transmission. Further, when the vehicle speed is lower than the predetermined vehicle speed, a lockup release command is output to the transmission.

However, the shift schedule has a normal shift schedule and a shift schedule for 4WD. The shift schedule for 4WD is a shift schedule in which the shift line is shifted to the high speed side with respect to the normal shift schedule.
FIG. 12 shows an example of the shift schedule. The solid line is an example of a shift schedule in which the normal shift line from the first speed to the second speed is used. The shift schedule in which the shift line in the broken line portion is shifted to the high speed side is an example of a 4WD shift schedule. Moreover, the code | symbol X in FIG. 12 is a line | wire of whether to start lockup.

Next, processing of the transmission controller 41 will be described with reference to FIG.
The transmission controller 41 operates every predetermined sampling period.
First, in step S300, it is determined whether or not the 4WD shift line flag TIS4FLG is ON. If the 4WD shift line flag TIS4FLG is ON, a 4WD shift schedule is selected in step S310. If the 4WD shift line flag TIS4FLG is OFF, a normal 4WD shift schedule (2WD shift line) is selected in step S320.

Subsequently, in step S330, it is determined whether or not the shift holding flag TKeep is ON. When the shift holding flag TKeep is ON, the process proceeds to step S350. On the other hand, when the shift holding flag TKeep is OFF, the process proceeds to step S340.
In step S340, based on the data of the selected shift schedule (shift diagram), the target gear ratio is determined based on the accelerator opening (or throttle valve opening) and the vehicle speed, and a shift command corresponding to the target gear ratio is issued. Output to the transmission 4.

In step S350, it is determined whether or not the lockup prohibition flag LUOFF is ON. When the lockup prohibition flag LUOFF is ON, the process proceeds to step S380. When the lockup prohibition flag LUOFF is OFF, the process proceeds to step S360.
In step S360, with reference to the data of the selected shift schedule (shift diagram), it is determined whether or not the lock-up state is established based on the accelerator opening (or throttle valve opening) and the vehicle speed.
In the case of the lock-up state, the process proceeds to step S370 and returns after outputting the lock-up command. If it is not in the lock-up state, the process proceeds to step S380.
In step S380, a lockup release command is output and the process returns.

(Operation / Action)
When the drive wheel accelerates and slips on a low μ road or when starting, the power of the generator is supplied to the motor and the driven wheel is driven by the drive torque of the motor. That is, it becomes a 4WD state (motor drive state). Further, when the acceleration slip of the driving wheel is settled, the motor driving stops and the 2WD state is set.
In the present embodiment, when the 4WD state (motor driving state) is reached, the lock-up clutch is prohibited from being engaged (referred to as a lock-up state), and in the lock-up state, the clutch is released. Further, by changing the shift module to the high speed side, it is difficult to shift at low speed.

Further, as shown in FIG. 14, when switching from the 4WD state to the 2WD state, the engine speed, that is, the rotation speed of the main drive wheel, waits for the drop to fall below the predetermined lower limit value LimΔN, and then for 2WD. It is possible to shift with the shift schedule.
FIG. 15 shows a time chart example.
This time chart example is an example of a 4WD state (four-wheel drive state) when starting and slipping.
Here, step S100 constitutes a motor drive state determination means. Steps S110 and S350 constitute lockup prohibiting means. Steps S180 to S210 constitute a lower limit setting means. Steps S120, S170, and S300 to S320 constitute shift schedule changing means.

(Effect of this embodiment)
(1) The motor drive state determination means determines whether or not the motor is in a motor drive state in which the motor is driven by the electric power of the generator and the drive torque is transmitted to the driven wheels. The lockup prohibiting means prohibits the lockup clutch from being engaged when the motor drive state is determined based on the determination by the motor drive state determination means.
Lockup is prohibited in a motor drive state such as a four-wheel drive state in which a drive torque is generated with respect to the driven wheel by the motor. As a result, it is possible to prevent the rotation speed of the main drive source from being lowered due to lockup. As a result, the power generation amount of the generator can be ensured to an appropriate value, and the drive torque control of the motor can be appropriately performed.
This means that, in the 4WD area, such as when starting and when slipping occurs (low μ road, etc.), 4WD driving is given priority over the engagement of the lock-up clutch in order to improve the driving performance when starting and on low μ roads. I will let you.

(2) The lower limit value setting means is based on the determination of the motor drive state determination means, and the lower limit value (limit value) of the rotational speed change rate of the main drive source when shifting from the motor drive state to the non-motor drive state. ) Is set. Then, the shift change is permitted after the rate of change in the rotational speed of the main drive source reaches the lower limit (limit value) set by the lower limit setting means.
A drop in engine rotation at the time of switching from the 4WD state (4WD) to the 2WD state (2WD) can be suppressed to a level where there is no sense of incongruity. That is, it is possible to reduce a shock at the time of switching the traveling mode.

(3) The lower limit value setting means sets the lower limit value of the rotational speed change rate to be smaller as the throttle opening TVO is larger.
When the throttle opening TVO is large, the lower limit value of the rotational speed change rate is decreased. That is, the smaller the throttle opening TVO, the smaller the engine speed drop when switching from the 4WD state (4WD) to the 2WD state (2WD). As a result, it is possible to more appropriately suppress a drop in engine rotation at the time of switching from 4WD to 2WD to a level that does not cause a sense of incongruity.

(4) The shift schedule changing means changes the shift schedule of the transmission to the high rotation side when the motor is driven. Then, when shifting from the non-motor driving state to the motor driving state, the shift schedule is changed by the shift schedule changing unit after the lock-up clutch is released by the lock-up prohibiting unit.
By releasing the lock-up clutch, the inertia for increasing the engine speed can be reduced. For this reason, at the time of switching from 2WD to 4WD, the lockup clutch is released first, so that the engine speed required for driving the motor can be increased faster. Responsiveness to the 4WD state is improved.

(Modification)
(1) In the above embodiment, after canceling the lockback prohibition in step S140, the shift schedule is changed to a 2WD shift schedule in step S170. It is not limited to this. As shown in FIG. 16, the lock-ack prohibition may be canceled in step S155 after step S150.
That is, the shift schedule changing means changes the shift schedule of the transmission to the high rotation side when the motor is driven. Then, when shifting from the motor drive state to a state not in the motor drive state, the shift schedule changed by the shift schedule change unit is restored, and then the prohibition of the fastening state by the lockup prohibition unit is released. .

Changing the shift schedule of the transmission to the high rotation side makes shifting difficult.
Further, after the shift schedule is switched, the lockup clutch is brought into the engaged state. As a result, the shift schedule is changed when the lock-up clutch is not engaged. As a result, the change in the vehicle acceleration due to the shift becomes smooth.
Further, since the lockup clutch is engaged after the shift schedule is changed, that is, after shifting to the high gear ratio, the shock at the time of engaging the lockup clutch can be reduced.
(2) The motor may be an AC motor. Moreover, you may have a battery other than a generator as electric power supply to a motor.
(3) The stepped automatic transmission is exemplified as the transmission, but a continuous transmission (CVT) may be used. FIG. 17 shows a shift diagram (shift schedule) of the continuously variable transmission (CVT).

1FL, 1FR Front wheels 1RL, 1RR Rear wheels 2 Engine 3 Motor 4 Transmission 7 Generator 8 4WD controller 8A Generator controller 8B Relay controller 8C Motor controller 8D Clutch controller 8E Surplus torque calculator 8F Target torque limiter 8G Surplus torque converter 8T Shift control unit 41 Transmission controller LimΔN Lower limit target rotational speed LUOFF Lock-up prohibition flag TIS4FLG 4WD shift line flag TKeep Shift hold flag TVO Throttle opening

Claims (6)

A main drive source for driving the main drive wheel, a transmission provided with a torque converter with a lock-up clutch interposed in a torque transmission path from the main drive source to the main drive wheel, a generator driven by the main drive source, In a vehicle driving force control device comprising at least a motor driven by the electric power of the generator, and driven wheels driven by the motor,
Motor driving state determination means for determining whether or not a motor driving state in which the motor is driven by electric power of the generator and driving torque is transmitted to the driven wheels;
When determining the motor driving state based on the determination of the motor driving state determination means, lockup prohibiting means for prohibiting the engagement state of the lockup clutch;
Equipped with a,
As a shift schedule of the transmission, there is a first shift schedule when the motor is driven and a second shift schedule when the motor is not driven, and the first shift schedule is a second shift schedule. On the other hand, the vehicle driving force control device is characterized in that the shift line has a schedule for shifting to the high speed side . Based on the determination of the motor drive state determination means, the apparatus includes lower limit value setting means for setting a limit value of the rotational speed change rate of the main drive source when shifting from the motor drive state to the non-motor drive state. 2. The vehicle driving force control apparatus according to claim 1, wherein the change of the shift schedule of the transmission is permitted after the rotational speed change rate of the main drive source becomes equal to or less than a limit value set by the value setting means. The main drive source is an internal combustion engine,
3. The vehicle driving force control apparatus according to claim 2, wherein the lower limit value setting means sets the limit value of the rotational speed change rate to be smaller as the throttle opening is larger. When the motor is driven, the shift schedule changing means for changing the shift schedule of the transmission to the high rotation side is provided.
When shifting from the motor driving state to a state not in the motor driving state, after canceling the shift schedule changed by the shift schedule changing unit, the prohibition of the fastening state by the lockup prohibiting unit is canceled. The driving force control device for a vehicle according to any one of claims 1 to 3, wherein the driving force control device is a vehicle. When the motor is driven, the shift schedule changing means for changing the shift schedule of the transmission to the high rotation side is provided.
The shift schedule is changed by the shift schedule changing means after the lockup clutch is released by the lockup prohibiting means when shifting from a state not in the motor driving state to the motor driving state. The vehicle driving force control apparatus according to any one of claims 1 to 4. The driving torque of the main driving source is transmitted to the main driving wheel via a transmission having a torque converter with a lock-up clutch, and the driven wheel is driven by a motor driven by electric power of a generator driven by the main driving source. In the vehicle driving force control method configured to be capable of driving,
In the motor driving state where the motor is driven by the electric power of the generator, the engagement state of the lock-up clutch is prohibited ,
A driving force control method for a vehicle, wherein when the motor is driven, the shift schedule of the transmission is changed to a high rotation side .

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