JP2008167586A - Vehicle drive control device - Google Patents

Abstract

The rotational direction of a rear wheel drive wheel is detected even in a low speed region where the wheel speed of a rear wheel drive wheel cannot be detected by an ABS wheel speed sensor.
In a vehicle drive control device, an electromagnetic clutch 11 is in a disconnected state (step S1), and a wheel speed Vw of rear wheels 1RL, 1RR is less than a first wheel speed determination threshold value Vwth1. (Step S2), the inverter 9 performs a three-phase short circuit (Step S3), and acquires and holds the rotation direction of the electric motor 3 as the rotation direction of the rear wheels 1RL and 1RR (Steps S6 to S8). Based on the rotation direction of the electric motor 3 and the rotation direction of the rear wheels 1RL, 1RR, the electromagnetic clutch 11 is controlled from the disconnected state to the connected state.
[Selection] Figure 8

Description

  The present invention relates to a vehicle drive control device capable of driving wheels with an electric motor.

In the vehicle drive device disclosed in Patent Document 1, a generator is driven by an engine, electric power generated by the generator is supplied to a motor, and torque of the motor is transmitted to drive wheels via a reduction gear. ing. In this device, a clutch is disposed between the motor and the rear wheel drive wheel, and when in the four-wheel drive state, the clutch is engaged and torque is transmitted from the motor to the rear wheel drive wheel.
JP 2006-187090 A

In the apparatus as described above, the rotation direction of the rear wheel drive wheel is specified based on the wheel speed of the rear wheel drive wheel detected by the ABS wheel speed sensor. As a result, when the clutch is re-engaged in order to change from the two-wheel drive state to the four-wheel drive state, the rotation direction and rotation number of the motor are matched with the rotation direction and rotation number of the drive wheel of the rear wheel drive wheel The clutch is engaged.
However, the ABS wheel speed sensor cannot detect the wheel speed in a low speed range (for example, 1.5 km / h or less) (detection accuracy is deteriorated). If the wheel speed cannot be detected, the rotational direction and the rotational speed of the rear wheel drive wheel and the motor cannot be matched, so that the clutch cannot be engaged and the four-wheel drive state cannot be achieved.
An object of the present invention is to detect the rotational direction of the rear wheel drive wheel even in a low speed range where the ABS wheel speed sensor cannot detect the wheel speed of the rear wheel drive wheel.

In order to solve the above-described problem, the vehicle drive control device according to the present invention is configured such that the intermittent mechanism is in the cutoff state and the wheel speed of the wheel detected by the wheel speed detecting means is set in accordance with the wheel speed. If it is less than the first threshold, the three-phase inverter that supplies the electric power from the generator to the three-phase inverter performs a three-phase short circuit, the motor rotation state detection means detects the rotation direction of the motor, and the intermittent mechanism control means , Obtaining the rotation direction of the motor detected by the motor rotation direction detection means as the rotation direction of the wheel, and controlling the intermittent mechanism from the disconnected state to the connected state based on the rotational direction of the motor and the rotational direction of the wheel do.
As a result, when the interrupting mechanism is in the shut-off state, the motor can rotate the wheel in the rotational direction in that the so-called accompanying torque due to the viscosity in the interrupting mechanism balances with the braking torque generated in the three-phase short circuit. In the same manner, the intermittent rotation control means acquires the rotation direction of the motor detected by the motor rotation direction detection means at this time as the rotation direction of the wheels.

  According to the present invention, even when the wheel speed becomes low, the rotation direction of the wheel can be obtained, and the intermittent mechanism is connected from the disconnected state to the connected state based on the rotational direction of the wheel and the rotational direction of the electric motor. It is possible to control from the two-wheel drive state to the four-wheel drive state.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(Constitution)
FIG. 1 is a schematic configuration diagram of the present invention, in which front wheels 1FL and 1FR are main drive wheels driven by an engine 2, and rear wheels 1RL and 1RR are standby drive wheels that can be driven by an electric motor 3. It is a wheel drive vehicle.
The driving force of the engine 2 is transmitted to the front wheels 1FL and 1FR via the automatic transmission 4 having a torque converter and the differential gear 5 in this order, and is also transmitted to the generator 7 via the V belt 6. The generator 7 generates electric power using the power transmitted via the V-belt 6, and the generated electric power is transmitted through the power cable 8 and converted from direct current to alternating current by a pulse width modulation (PWM) inverter 9. It is supplied to the electric motor 3. The driving force of the electric motor 3 is transmitted to the rear wheels 1RL and 1RR through the speed reducer 10, the electromagnetic clutch 11, and the differential gear 12 in this order.

The output of the engine 2 is controlled by the engine controller 20. The engine controller 20 controls the output of the engine 2 by adjusting the rotation angle of the throttle motor 23 connected to the throttle valve 22 in accordance with the accelerator opening Acc detected by the accelerator sensor 21.
The output voltage of the generator 7 is controlled by the 4WD controller 24. The 4WD controller 24 controls the output voltage Vg of the generator 7 by adjusting the field current Ig via an IC regulator built in the generator 7. As a circuit power source of the IC regulator, a vehicle 14V battery 25 is used. As shown in FIG. 2A, when the output voltage Vg of the generator 7 is less than the battery voltage Vb, the battery voltage Vb is used. The output voltage Vg may be used when the voltage is equal to or higher than the battery voltage Vb, or the battery voltage Vb may be used at all times as shown in FIG. In addition, 7a in a figure is a rotor coil through which the field current Ig flows.

  In addition, a junction box 26 provided in the middle of the power cable 8 includes a main relay that turns ON / OFF the power supply to the electric motor 3 in response to a relay control command from the 4WD controller 24, an energization current Ia, and a generator voltage. A current sensor and a voltage detection circuit for monitoring Vg and the motor induced voltage Vm by the 4WD controller 24 are incorporated.

  The output of the electric motor 3 is controlled by the 4WD controller 24. The 4WD controller 24 controls the output of the electric motor 3 by adjusting the duty ratio of the switching element built in the inverter 9 and adjusting the field current Im of the electric motor 3. The inverter 9 is electrically braked (hereinafter referred to as a motor brake) to the electric motor 3 by a three-phase short circuit according to a brake control command from the 4WD controller 24 (specifically, a motor brake control unit 24F described later). ). Further, the thermistor for monitoring the inverter temperature with the 4WD controller 24 is attached to the inverter 9, and the motor rotation sensor (motor) for monitoring the motor rotation speed Nm and the motor temperature with the 4WD controller 24 is attached to the electric motor 3. A resolver 3a and a thermistor are attached.

Further, the electromagnetic clutch 11 is controlled in power transmission from the electric motor 3 to the rear wheels 1RL and 1RR by controlling the energization of the excitation current in accordance with the clutch control command from the 4WD controller 24.
The 4WD controller 24 includes an engine rotation sensor that detects the engine speed Ne, an accelerator sensor that detects the accelerator opening Acc, and wheel speed sensors 27FL to 27RR that detect the wheel speeds Vw _{FL to} Vw _RR. A signal is also input.

  FIG. 3 is a block diagram of calculation processing executed by the 4WD controller 24. The 4WD controller 24 includes a target motor torque calculation unit 24A, a motor required power calculation unit 24B, a power generation control unit 24C, a motor control unit 24D, and a clutch control unit. 24E and a motor brake control unit 24F are provided. Although the detailed description of the control of the main relay is omitted, the 4WD controller 24 outputs a relay control command to the main relay to supply power to the electric motor 3 when driving the electric motor 3. It is assumed that the control is in the ON state.

First, calculation processing executed by the target motor torque calculation unit 24A will be described with reference to the block diagram of FIG.
In slip speed calculating section 30, the front wheels 1FL, calculates the slip speed [Delta] V _F of 1FR. The slip speed [Delta] V _F, for example, as shown in the following equation (1), the front wheels 1FL, from the average wheel speeds of 1FR, the rear wheels 1RL, calculated by subtracting the average wheel speed of 1RR.
ΔV _F = (Vw _FL + Vw _FR ) / 2− (Vw _RL + Vw _RR ) / 2 (1)

In the first motor torque calculation unit 31, with reference to the control map in FIG calculates the first motor torque Tm1 in accordance with the slip speed [Delta] V _F. Here, the control map, the slip on the horizontal axis velocity [Delta] V _F, the vertical axis and the first motor torque Tm1, the slip speed [Delta] V _F is increased, the first motor torque Tm1 is set so as to increase accordingly Yes.
On the other hand, the vehicle speed calculation unit 32 calculates the vehicle speed V according to the selected low value of the wheel speeds Vw _{FL to} Vw _RR and the total driving force F of the vehicle. Here, the total driving force F is obtained by the sum of the front wheel driving force estimated from the torque converter slip ratio and the rear wheel driving force estimated from the target motor torque Tm ^* .

The second motor torque calculator 33 calculates the second motor torque Tm2 according to the vehicle speed V and the accelerator opening Acc with reference to the control map in the figure. Here, in the control map, the horizontal axis is the accelerator opening Acc, the vertical axis is the second motor torque Tm2, and when the accelerator opening Acc increases, the second motor torque Tm2 increases accordingly, and the vehicle speed V The second motor torque Tm2 is set to be smaller as the value is higher.
Then, the target motor torque calculating section 34, based on the first motor torque Tm1 to select high values of the second motor torque Tm2, the rear wheel speed _Vw RL · _{Vw RR,} and the vehicle speed V, the rear wheels 1RL, 1RR To a value that suppresses the acceleration slip (known traction control), and a final target motor torque Tm ^* is calculated.

Next, in the required motor power calculation unit 24B of FIG. 3, the required motor power Pm ^* required for the electric motor 3 is set to the target motor torque Tm ^* and the motor rotation speed Nm as shown in the following equation (2). Calculate according to
Pm ^* = Tm ^* × Nm (2)
Next, calculation processing executed by the power generation control unit 24C of FIG. 3 will be described with reference to the block diagram of FIG.
The target power calculation unit 40 calculates the target power Pg ^* to be output by the generator 7 according to the required motor power Pm ^* and the motor efficiency ηm as shown in the following equation (3).
Pg ^* = Pm ^* / ηm (3)

The limit value calculation unit 41 calculates limit values PL1 and PL2 for the output power.
Here, the limit value PL1 is an upper limit value that can suppress the belt slip of the V belt 6, and as shown in the following equation (4), the torque upper limit value TL that can be transmitted by the V belt 6, the generator rotational speed Ng, It is calculated according to the generator efficiency ηg.
PL1 = TL × Ng × ηg (4)
The limit value PL2 is an upper limit value that can suppress engine stall or drivability deterioration due to overload of the engine 2, and may be calculated according to the engine speed Ne or may be a predetermined value.
The final target power calculation unit 42 calculates the value selected by the target power Pg ^* and the limit values PL1 and PL2 as the final target power Pg ^* .

The control processing unit 43 controls the field current Ig of the generator 7 so that the generator 7 outputs the target power Pg ^* . Specifically, as shown in FIG. 6, the field current Ig is controlled by feedback control so that the target power Pg ^* matches the actual output power Pg.
That is, the output power calculation unit 43a calculates the actual output power Pg (= Vg × Ia) by multiplying the generator voltage Vg and the energization current Ia.
Then, the target field current calculation unit 43b calculates a target field current Ig ^* such that the deviation ΔPg between the actual output power Pg and the target power Pg ^* is zero.
Then, in the field current control unit 44c, the field current Ig flowing through the rotor coil 7a is passed through the IC regulator so that the deviation ΔIg between the actual field current Ig and the target field current Ig ^* becomes zero. Control. The actual field current Ig is detected by a current sensor.

Next, in the motor control unit 24D of FIG. 3, for example, as shown in FIG. 7, known vector control is performed according to the target motor torque Tm ^* and the motor rotational speed Nm, and the target motor torque Tm ^* is output. Thus, the duty ratio of the switching element built in the inverter 9 and the field current Im of the electric motor 3 are adjusted.
Next, in the clutch control unit 24E of FIG. 3, when the target motor torque Tm ^* is 0, the electromagnetic clutch 11 is controlled to be in a non-engaged state, thereby transmitting power from the electric motor 3 to the rear wheels 1RL and 1RR. When the target motor torque Tm ^* is greater than 0 by shutting off and setting the target motor torque Tm ^* to greater than 0, the electromagnetic clutch 11 is controlled to be in the engaged state so that the four-wheel drive state is established, and the electric motor 3 starts the rear wheels 1RL, 1RR. Transmit power to
Next, the motor brake control unit 24 </ b> F shown in FIG. 3 outputs a brake control command to the inverter 9. The inverter 9 performs a three-phase short circuit according to the brake control command and applies the motor brake to the electric motor 3.

As described above, the 4WD controller 24 performs predetermined processing by each component.
FIG. 8 shows a processing procedure in the 4WD controller 24 for realizing the present invention.
As shown in FIG. 8, when the process is started, it is first determined in step S1 whether or not the vehicle is in a four-wheel drive state (four-wheel drive mode). That is, it is determined whether or not the rear wheel 1RL, 1RR is driven by the electric motor 3 with the electromagnetic clutch 11 engaged. Here, this determination is performed until the vehicle is not in the four-wheel drive state, and when the vehicle is not in the four-wheel drive state (when the vehicle is in the two-wheel drive state), the process proceeds to step S2. For example, this determination is performed by the clutch control unit 24E.

In step S2, it is determined whether or not the wheel speed Vw of the rear wheels 1RL and 1RR is less than a first wheel speed determination threshold value Vwth1. Here, the rear wheels used to determine 1RL, as the wheel speed Vw of 1RR, each wheel 1RL, wheel speed _Vw RL of 1RR, either one (for example, smaller) of the _{Vw RR} and rear wheels 1RL, wheels 1RR speed _Vw RL, the average value of _{Vw RR (Vw RL + Vw RR} ) / 2) and the like.

Here, the determination is performed until the wheel speed Vw of the rear wheels 1RL and 1RR becomes less than the first wheel speed determination threshold value Vwth1, and the wheel speed Vw of the rear wheels 1RL and 1RR is determined as the first wheel speed determination. If it is less than the threshold value Vwth1 (Vw <Vwth1), the process proceeds to step S3.
Further, the first wheel speed determination threshold value Vwth1 is a value (for example, 1.5 km / h + α) larger than a value (for example, 1.5 km / h) that can be detected by the wheel speed sensors 27RL and 27RR.
In step S3, a three-phase short circuit is performed. That is, the motor brake control unit 24F outputs a brake control command for the inverter 9, and puts the motor brake for the electric motor 3 into an operating state.

FIG. 9 shows the configuration of the switching element built in the inverter 9.
As shown in FIG. 9, switching elements 9 a and 9 b are arranged in the inverter 9 corresponding to the positive electrode and the negative electrode of each phase of the electric motor 3. In such a configuration, all the switching elements 9b on the negative electrode (lower arm) side are turned on, while all the switching elements 9a on the positive electrode (upper arm) side are turned off, thereby performing a three-phase short circuit. As a result, a short-circuit current flows in the electric motor 3 and a braking torque that serves as a motor brake is generated.

  Subsequently, in step S4, it is determined whether or not the motor rotation speed Nm (detected value of the motor rotation sensor (motor resolver) 3a) is less than a motor rotation speed determination threshold Nmth. Here, this determination is performed until the motor rotation speed Nm becomes less than the motor rotation speed determination threshold value Nmth, and when the motor rotation speed Nm becomes less than the motor rotation speed determination threshold value Nmth (Nm <Nmth). ), Go to step S5.

In step S5, it is determined whether or not a predetermined time has elapsed after the processing of step S5 is started (from when the motor rotation speed Nm becomes less than the motor rotation speed determination threshold Nmth in step S4). To do. Here, the determination is performed until a predetermined time elapses, and when the predetermined time elapses, the process proceeds to step S6.
In step S6, the rotation direction of the electric motor 3 detected by the motor rotation sensor (motor resolver) 3a is detected as the rotation direction of the rear wheels 1RL and 1RR. Alternatively, the three-phase current flowing in the electric motor 3 is detected, the rotation direction of the electric motor 3 is detected from the direction of the q-axis current obtained by converting the detected three-phase current, and the detected rotation direction is set to the rear wheel 1RL, It is detected as the rotation direction of 1RR. For example, at the time of a three-phase short circuit, when the electric motor 3 is rotating forward, the q-axis current is negative, and when the electric motor 3 is rotating backward, the q-axis current is positive. The direction of rotation of the electric motor 3 is detected from the direction of the q-axis current.

Subsequently, in step S7, it is determined whether or not the wheel speed Vw of the rear wheels 1RL and 1RR is equal to or higher than a second wheel speed determination threshold value Vwth2. Here, the rear wheels used to determine 1RL, as a wheel speed Vw of 1RR, similarly to the step S2, the wheel 1RL, wheel speed _Vw RL of 1RR, either one (for example, smaller) of the _{Vw RR} Ya An average value (Vw _RL + Vw _RR ) / 2) of the wheel speeds Vw _RL and Vw _RR of the rear wheels 1RL and 1RR can be given. If the wheel speed Vw of the rear wheels 1RL and 1RR is equal to or higher than the second wheel speed determination threshold value Vwth2, the process proceeds to step S8, and the wheel speed Vw of the rear wheels 1RL and 1RR is used for the second wheel speed determination. If it is less than the threshold value Vwth2, the process is repeated from step S6. That is, the rotation direction of the rear wheels is detected until the wheel speed Vw of the rear wheels 1RL and 1RR becomes equal to or higher than the second wheel speed determination threshold value Vwth2.

  Further, the second wheel speed determination threshold value Vwth2 is different from the first wheel speed determination threshold value Vwth1 and can be detected by the wheel speed sensors 27RL and 27RR (for example, 1.. 5 km / h) (for example, 1.5 km / h + γ). The second wheel speed determination threshold value Vwth2 may be the same value as the first wheel speed determination threshold value Vwth1.

In step S8, the most recently detected rotation direction of the rear wheels, that is, the rear wheels 1RL, 1RR detected at the timing when the wheel speed Vw of the rear wheels 1RL, 1RR becomes the predetermined threshold value Vwth2 in step S7. Holds (stores) the rotation direction (information).
Subsequently, in step S9, the three-phase short circuit controlled by the motor brake control unit 24F is released. Then, the process shown in FIG. 8 ends (the process starts again from step S1).

(Operation, action and effect)
The operation, action and effect are as follows.
Now, it is assumed that the front wheels 1FL and 1FR driven by the engine 2 have accelerated and slipped due to a large depression of the accelerator pedal or a low friction coefficient of the road surface such as a rainy road, a snowy road, and a frozen road.
At this time, the target motor torque Tm ^* is calculated with an increase in growth and the accelerator opening Acc of the front wheel slip speed [Delta] V _F, with power generation of the generator 7 is started in response to this, powering the start of the electric motor 3 Is done. Thus, by converting the rotational energy lost by the acceleration slip into electric energy, the output of the engine 2 is suppressed, and the acceleration slip of the front wheels 1FL and 1FR can be suppressed.

Further, by supplying the electric power generated by the generator 7 to the electric motor 3 and driving the rear wheels 1RL and 1RR by the electric motor 3, that is, in a four-wheel drive state, not only the energy efficiency is improved, Smooth and stable starting performance and running performance can be exhibited.
Moreover, to calculate the required power Pm required for the electric motor 3 ^*, calculates the required power Pm ^* target power generator 7 to be output from the Pg ^*, and the target power Pg ^* is the actual output power Pg Since the field current Ig of the generator 7 is controlled so as to match, the generator 7 can accurately supply the necessary electric power Pm ^* required for the electric motor 3 and accurately output the target motor torque Tm ^*. be able to.

Further, the field current Ig of the generator 7 is detected by a current sensor, and feedback control is performed so that the actual field current Ig follows the target field current Ig ^* , so that the output power Pg can be reliably set to the target power Pg ^*. Can be followed.
From this state, when the acceleration slip of the front wheels 1FL and 1FR is suppressed or the vehicle speed V exceeds a predetermined value (for example, 60 km / h) and the target motor torque Tm ^* becomes substantially zero, the electromagnetic clutch 11 is disconnected ( The four-wheel drive is changed to the two-wheel drive.

  In the two-wheel drive state, when the wheel speed Vw of the rear wheels 1RL and 1RR becomes less than the first wheel speed determination threshold value Vwth1, a three-phase short circuit is performed and the motor brake for the electric motor 3 is activated. A state is reached (step S1 → step S2 → step S3). The electric motor 3 used as the rotation direction of the rear wheels 1RL and 1RR when a predetermined time elapses after the condition that the motor rotation speed Nm is less than the motor rotation speed determination threshold value Nmth is satisfied. Is detected (step S4 → step S5 → step S6).

FIG. 10 is a schematic diagram showing a state of torque transmission between the rear wheels 1RL, 1RR and the electric motor 3 when the clutch 11 is released.
In the clutch 11 in the released state, the rotation of the rear wheels 1RL and 1RR with respect to the object to be engaged with the rear wheels 1RL and 1RR, that is, the electric motor 3 (rotation drive shaft) by the action of viscosity at the engagement portion (arrows shown in the figure). (Rotation in the direction indicated by A), that is, a so-called turning torque is generated. For this reason, if there is no motor brake, the electric motor 3 attempts to rotate freely. On the other hand, when the motor brake is applied, the braking torque acts in the opposite direction to the turning torque, so the turning torque (torque in the direction of arrow B shown in the figure) and the braking torque. (The braking torque in the direction indicated by the arrow C shown in the figure) balances the electric motor with the same rotation direction as the rear wheels 1RL, 1RR (specifically, the drive shafts of the rear wheels 1RL, 1RR). The number settles, for example, near zero (becomes stable).

Also, when the wheel rotation direction changes from positive to negative (changes from forward to backward), the electric motor 3 will rotate due to inertia if the motor brake is not applied, but by applying the motor brake Due to the action of the braking torque, the rotation of the electric motor 3 comes to settle quickly near zero (in this case, in the opposite rotation direction).
For this reason, when the motor rotational speed Nm satisfies the condition that the motor rotational speed determination threshold value Nmth is less than the threshold value Nmth and a predetermined time has elapsed from the time when the condition is satisfied, the rotational speed of the electric motor 3 is settled. The rotation direction of the electric motor 3 is detected (assuming that the step S4 → the step S5 → the step S6).

  The rotation direction of the electric motor 3 is detected until the wheel speed Vw of the rear wheels 1RL, 1RR driven by the electric motor 3 becomes equal to or higher than a predetermined threshold value Vwth2, and the rear wheels driven by the electric motor 3 are detected. When the wheel speed Vw becomes equal to or higher than a predetermined threshold value Vwth2, the detected value at that time is held as the latest detected value, the three-phase short circuit is canceled, and the motor brake operation of the electric motor 3 is released. (Step S7 → Step S8 → Step S9).

In the region where the wheel speed Vw of the rear wheel is equal to or higher than the predetermined threshold value Vwth2, the rotation direction of the held rear wheels 1RL, 1RR (the rotation direction of the electric motor 3 that becomes the latest detected value) is matched. In addition, the rotation direction of the electric motor 3 is controlled to engage the clutch 11.
As described above, whether or not the rotational speed of the electric motor 3 has settled due to the balance between the turning torque due to the viscosity of the clutch 11 and the braking torque by the electric motor 3 is determined as a motor rotational speed determination threshold value Nmth. Therefore, the motor rotation speed determination threshold value Nmth is a rotation of the electric motor 3 in which the rotation torque due to the viscosity of the clutch 11 and the braking torque by the electric motor 3 are balanced and the rotation is stable. It is set to a value slightly larger than the number.

  Here, for example, when starting, if the clutch 11 is in the engaged state and is in the four-wheel drive state, the rotation direction of the electric motor 3 is set to the rotation direction of the rear wheels 1RL and 1RR, so that two-wheel drive is performed later. Even if it becomes a state, on the assumption that the wheel speed Vw of the rear wheels 1RL, 1RR can be detected by the wheel speed sensors 27RL, 27RR, the electric motor is based on the initially detected rotation direction of the rear wheels 1RL, 1RR. 3 is controlled, and the clutch 11 can be re-engaged. That is, the wheel speed sensors 27RL and 27RR are merely for detecting the wheel speed Vw of the rear wheels 1RL and 1RR (not for detecting the rotation direction), but the wheel speed sensors 27RL and 27RR are for detecting the rear wheels 1RL and 27RR. If the wheel speed Vw of 1RR can be continuously detected, it is based on the initially detected rotation direction of the rear wheels 1RL and 1RR on the assumption that the traveling direction (forward direction or backward direction) is maintained. The clutch 11 can be engaged by controlling the rotation direction of the electric motor 3.

  However, the wheel speed sensors 27RL and 27RR cannot detect the wheel speeds Vw of the rear wheels 1RL and 1RR at a low speed (detection accuracy decreases). Therefore, when the vehicle travels at a low speed (for example, when the vehicle speed decreases from the normal travel and the vehicle travels at a low speed), the wheel speed sensors 27RL and 27RR cannot detect the wheel speed Vw of the rear wheels 1RL and 1RR. , 1 RR rotation direction is maintained (while the rotation direction information is maintained), and the clutch 11 cannot be engaged.

  On the other hand, when the wheel speed sensors 27RL and 27RR become low speed (less than the first wheel speed determination threshold value Vwth1), as described above, the motor brake is applied to change the rotation direction of the electric motor 3. After that, when the wheel speed sensors 27RL and 27RR can detect the wheel speed Vw of the rear wheels 1RL and 1RR (when the second wheel speed determination threshold value Vwth2 or more), By holding the rotation direction of the electric motor 3, the rotation direction of the held electric motor 3 is set as the rotation direction of the rear wheels 1RL, 1RR, and the engagement control of the clutch 11 is performed based on the rotation direction of the rear wheels 1RL, 1RR. Thus, the two-wheel drive state can be changed to the four-wheel drive state. That is, even when the vehicle speed is once reduced and the wheel speed sensors 27RL and 27RR cannot detect the wheel speed Vw of the rear wheels 1RL and 1RR, the rotation direction of the rear wheels 1RL and 1RR can be detected.

  When the wheel speed sensors 27RL and 27RR can detect the wheel speed Vw of the rear wheels 1RL and 1RR (when the second wheel speed determination threshold value Vwth2 or more), the wheel speed sensors 27RL and 27RR are Based on the detected wheel speed Vw of the rear wheels 1RL and 1RR (by monitoring the wheel speed Vw of the rear wheels 1RL and 1RR again), the rotational direction of the rear wheels 1RL and 1RR can be specified.

That is, in the speed region in which the wheel speed sensors 27RL and 27RR can detect the wheel speed Vw of the rear wheels 1RL and 1RR, the wheel speed sensors 27RL and 27RR detect the wheel speed Vw based on the wheel speed Vw of the rear wheels 1RL and 1RR. It is also possible to specify the rotational direction of the rear wheels 1RL, 1RR. For this reason, in order to be able to specify the rotational direction of the rear wheels 1RL, 1RR based on the wheel speed Vw of the rear wheels 1RL, 1RR detected by the wheel speed sensors 27RL, 27RR, The first and second wheel speed determination threshold values Vwth1 and Vwth2 are set to values larger than values (for example, 1.5 km / h) that can be detected by the wheel speed sensors 27RL and 27RR.
In addition, the said embodiment can also be implement | achieved by the following structures.
That is, when traveling at high speed, the vehicle traveling direction can be detected by the acceleration sensor, and the rotational direction of the wheel can be detected from the detected vehicle traveling direction.

  In the description of the embodiment, the electric motor 3 realizes an electric motor that can drive wheels, and the inverter 9 realizes a three-phase inverter that supplies electric power from a generator to the electric motor. The wheel speed sensors 27FL to 27RR (particularly 27RL and 27RR) realize wheel speed detecting means for detecting the wheel speed of the wheel, and the motor rotation sensor (motor resolver) 3a detects the rotation state of the electric motor. The motor rotation state detecting means is realized, the electromagnetic clutch 11 realizes an intermittent mechanism capable of interrupting transmission of power between the electric motor and the wheel, and the clutch control unit 24E Intermittent mechanism control means that controls disconnection and connection, and makes the rotation direction of the electric motor and the rotation direction of the wheel coincide with each other to change from the disconnected state to the connected state. The three-phase inverter when the wheel speed of the wheel detected by the wheel speed detecting means is less than a first threshold value set corresponding to the wheel speed. Performs a three-phase short circuit, the motor rotation state detection means detects the rotation direction of the motor, and the intermittent mechanism control means sets the rotation direction of the motor detected by the motor rotation direction detection means as the rotation direction of the wheels. Acquiring and controlling the intermittent mechanism from the disconnected state to the connected state based on the rotational direction of the electric motor and the rotational direction of the wheel is realized.

It is a schematic block diagram of this invention. It is a power supply circuit of an IC regulator. It is a block diagram of the arithmetic processing performed with a 4WD controller. It is a block diagram of a target motor torque calculation part. It is a block diagram of a power generation control unit. It is a block diagram of a control processing part. It is a block diagram of a motor control part. It is a flowchart which shows the arithmetic processing performed with 4WD controller. It is a figure which shows the structure of the switching element incorporated in the inverter used for description of a three-phase short circuit. It is a schematic diagram which shows the transmission state of the torque between a rear-wheel and an electric motor when the clutch is open | released.

Explanation of symbols

  1FL, 1FR front wheel, 1RL, 1RR rear wheel, 2 engine, 3 electric motor, 3a motor rotation sensor (motor resolver), 4 automatic transmission, 5 differential gear, 6 V belt, 7 generator, 8 power cable, 9 inverter, DESCRIPTION OF SYMBOLS 10 Reduction gear, 11 Electromagnetic clutch, 12 Differential gear, 20 Engine controller, 21 Acceleration sensor, 22 Throttle valve, 23 Throttle motor, 244WD controller, 24A Target motor torque calculation part, 24B Motor required power calculation part, 24C Power generation control part 24D motor control unit, 24E clutch control unit, 24F motor brake control unit, 25 14V battery, 26 junction box

Claims (4)

An electric motor capable of driving wheels;
A three-phase inverter that supplies power from the generator to the motor;
Wheel speed detecting means for detecting the wheel speed of the wheel;
Motor rotation state detection means for detecting the rotation state of the motor;
An intermittent mechanism capable of interrupting transmission of power between the electric motor and the wheel;
Intermittent mechanism control means for controlling the disconnection and connection of the intermittent mechanism, the intermittent mechanism control means for matching the rotation direction of the electric motor and the rotation direction of the wheel to make the connection state from the cutoff state
When the wheel mechanism of the wheel detected by the wheel speed detecting means is less than a first threshold value set corresponding to the wheel speed, the three-phase inverter is three-phase While performing a short circuit, the motor rotation state detection means detects the rotation direction of the motor, and the intermittent mechanism control means obtains the rotation direction of the motor detected by the motor rotation direction detection means as the rotation direction of the wheels. A vehicle drive control device that controls the intermittent mechanism from a disconnected state to a connected state based on the rotational direction of the electric motor and the rotational direction of the wheels.   The intermittent mechanism control means satisfies a condition in which the rotation speed of the electric motor is less than a predetermined threshold set corresponding to the rotation speed, and a period satisfying the condition corresponds to the period. 2. The vehicle drive control device according to claim 1, wherein the motor rotation direction detected by the motor rotation direction detection unit is acquired as the rotation direction of the wheel when the predetermined threshold value is exceeded.   The motor rotation state detection means detects a three-phase current flowing through the motor, converts the detected three-phase current into a q-axis current, and based on the converted direction of the q-axis current, the rotation direction of the motor The vehicle drive control device according to claim 1, wherein the vehicle drive control device is detected.   The intermittent mechanism control means is configured to determine a rotation direction of the wheel acquired when the intermittent mechanism is in an interrupted state and a wheel speed of the wheel detected by the wheel speed detection means is less than the first threshold. The control for switching the interrupting mechanism from the shut-off state to the connected state is performed even when the wheel speed of the wheel is equal to or higher than a second threshold value set corresponding to the wheel speed. Item 4. The vehicle drive control device according to any one of Items 1 to 3.

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