JP4305409B2 - Vehicle drive control device - Google Patents

Description

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

Conventionally, for example, in a standby type four-wheel drive vehicle in which front wheels are driven by an engine and rear wheels can be driven by an electric motor, when switching from four-wheel drive to two-wheel drive, the drive torque of the electric motor is substantially zero. After that, it has been proposed to disengage the clutch between the electric motor and the rear wheel (see Patent Document 1).
JP 2004-142472 A

However, as in the conventional example described in Patent Document 1, if the clutch is disengaged after simply setting the driving torque of the electric motor to 0, the electric motor rotates by inertia, and the vehicle is rotated before this inertia rotation stops. When the vehicle stops, the motor sound is heard even though there is no running sound of the vehicle, which gives the passenger a sense of incongruity.
For this reason, it is conceivable to apply electric braking (also referred to as motor braking) to the electric motor. However, since this electric braking causes heat generation of the electric motor, the electric motor may overheat depending on the time to apply electric braking. There is a possibility of deterioration.
Accordingly, the present invention has been made paying attention to the above-described problem, and can reduce a sound generated when the electric motor rotates by inertia before the vehicle stops, and can suppress a temperature increase of the electric motor to a minimum. An object of the present invention is to provide a drive control device.

  In order to solve the above-described problems, a vehicle drive control device according to the present invention includes a motor that can drive a wheel, and an intermittent mechanism that can interrupt transmission of power between the motor and the wheel. A drive control device, wherein when the driving of the wheel by the motor is stopped and the transmission of power is interrupted by the intermittent mechanism, the motor is electrically connected so that the inertial rotation of the motor stops when the wheel stops rotating. It is characterized by applying braking.

  According to the present invention, when the wheel drive by the motor is stopped and the transmission of power is interrupted by the interrupt mechanism, the motor is electrically braked so that the inertial rotation of the motor stops when the wheel rotation stops. By applying the noise, it is possible to reduce the sound when the electric motor rotates by inertia before the vehicle stops. In addition, when the inertial rotation of the electric motor stops before the vehicle stops, such as when the vehicle slowly decelerates, the electric braking to the electric motor can be deactivated. The temperature rise can be suppressed to the minimum, and the electric motor can be protected from overheating deterioration.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the present invention, in which the front wheels 1FL and 1FR are main driving wheels driven by the engine 2 and the rear wheels 1RL and 1RR are auxiliary driving wheels that can be driven by the 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 an automatic transmission 4 having a torque converter and a differential gear 5 in 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 via 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. Further, the inverter 9 applies electric braking (hereinafter referred to as motor braking) to the electric motor 3 by being short-circuited in three phases according to a brake control command from the 4WD controller 24. Further, the inverter 9 is provided with a thermistor for monitoring the inverter temperature by the 4WD controller 24, and the electric motor 3 has a motor rotation sensor and thermistor for monitoring the motor rotation speed Nm and the motor temperature by the 4WD controller 24. Is attached.

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 arithmetic processing executed by the 4WD controller 24. The target motor torque calculation unit 24A, the motor required power calculation unit 24B, the power generation control unit 24C, the motor control unit 24D, and the clutch control unit 24E. And a motor brake control unit 24F. 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 calculates the slip speed [Delta] V _F of the front wheels 1FL · 1FR. The slip speed [Delta] V _F, for example, as shown in the following formula (1), from an average wheel speed of the front wheels 1FL · 1FR, calculated by subtracting the average wheel speed of the rear wheels 1RL · 1RR.
ΔV _F = (Vw _FL + Vw _FR ) / 2− (Vw _RL + Vw _RR ) / 2 (1)

The first motor torque calculator 31 calculates the first motor torque Tm1 according to the slip speed ΔV _F with reference to the control map in the figure. Here, the horizontal axis represents the slip speed ΔV _F , the vertical axis represents the first motor torque Tm1, and when the slip speed ΔV _F increases, the first motor torque Tm1 increases 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, in the target motor torque calculation unit 34, the selected high values of the first motor torque Tm1 and the second motor torque Tm2 are set to the rear wheels 1RL and 1RR based on the rear wheel speeds Vw _RL and Vw _RR and the vehicle speed V. The final target motor torque Tm ^* is calculated by limiting the value to a value that suppresses the acceleration slip (known traction control).

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 a selected low value of 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 the 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 rotation 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 motor is shut off and the target motor torque Tm ^* is greater than 0, the electromagnetic clutch 11 is controlled to be engaged to transmit power from the electric motor 3 to the rear wheels 1RL and 1RR.

Next, the calculation processing of the first embodiment executed by the motor brake control unit 24F of FIG. 3 will be described according to the flowchart of FIG.
In step S1, it is determined whether or not the electromagnetic clutch 11 is in the non-engaged state (OFF) and the transmission of power from the electric motor 3 to the rear wheels 1RL and 1RR is interrupted. Here, when the electromagnetic clutch 11 is in the non-engaged state (OFF), it is determined that there is a possibility that the electric motor 3 is rotating by inertia, and the process proceeds to Step S5 described later. On the other hand, when the electromagnetic clutch 11 is in the engaged state (ON), it is determined that wheel driving by the electric motor 3 is being performed, and the process proceeds to step S2.

In step S2, the control flag F is reset to “0”.
In step S3, and it resets the initial value N ₀ of the motor rotation speed Nm is set in step S8 to be described later.
In the subsequent step S4, output of the brake control command for the inverter 9 is stopped, the motor brake for the electric motor 3 is controlled to the non-actuated state (OFF), and then the process returns to the predetermined main program.

  On the other hand, in step S5, which shifts from step S1, it is determined whether or not the motor speed Nm is equal to or greater than a predetermined value Nm1 (for example, a value corresponding to a vehicle speed of 10 km / h). When this determination result is Nm <Nm1, it is determined that the electric motor 3 is not inertially rotated, or even if it is inertially rotated, the motor sound is not so loud as to give a sense of incongruity to the occupant, and the process proceeds to step S2. To do. On the other hand, when the determination result is Nm ≧ Nm1, it is determined that the electric motor 3 is inertially rotating and the motor sound may give a sense of discomfort to the occupant, and the process proceeds to step S6.

  In step S6, whether or not the inertial rotation of the electric motor 3 is faster than the rotation of the rear wheels 1RL and 1RR, that is, the motor rotation speed Nw corresponding to the average wheel speed of the rear wheels. Determine if greater than. The motor speed Nw is a value obtained by multiplying the average wheel speed of the rear wheels by the reduction ratio of the speed reducer 10 and the differential gear 12. The motor rotation speed Nw corresponding to the selected high value of the rear wheel speed may be used instead of the motor rotation speed Nw corresponding to the average wheel speed of the rear wheels. Here, when the determination result is Nm ≦ Nw, it is determined that the inertial rotation of the electric motor 3 is stopped before the rotation of the rear wheels 1RL and 1RR is stopped, and the process proceeds to step S2. On the other hand, when the determination result is Nm> Nw, it is determined that the inertial rotation of the electric motor 3 continues even after the rotation of the rear wheels 1RL and 1RR is stopped, and the process proceeds to step S7.

In step S7, it is determined whether or not the control flag F is reset to “0”. When the determination result is F = 0, it is determined that it is immediately after detecting inertial rotation of the electric motor 3, and the process proceeds to step S8.
In step S8, the control flag F is set to “1”.
In step S9, the process proceeds after setting the motor rotational speed Nm of the point as an initial value N ₀ in step S10.

On the other hand, the determination result at Step S7 is when it is F = 1, the process moves it is determined that the already set the initial value N ₀ directly to step S10.
In step S10, it is determined whether or not the reduction amount ΔN (= N ₀ −Nm) of the motor rotation speed Nm from the initial value N ₀ is equal to or greater than a predetermined value ΔN ₁ (for example, 3000 rpm). When the determination result is ΔN <ΔN _1, it is determined that the inverter 9 and the electric motor 3 do not tend to overheat, and the process proceeds to step S11.

In step S11, a brake control command for the inverter 9 is output, the motor brake for the electric motor 3 is controlled to be in an operating state (ON), and then the process returns to a predetermined main program.
On the other hand, the determination result of step S10 is at a .DELTA.N ≧ .DELTA.N _1, the inverter 9 and the electric motor 3 is shifted to the step S4 it is determined to be in the overheated tendency by a motor brake.
From the above, the inverter 9 and the electric motor 3 correspond to the “motor”, and the electromagnetic clutch 11 corresponds to the “interruption mechanism”. Further, the process of step S6 corresponds to “rotation estimation means”, and the processes of steps S1 to S11 excluding step S6 correspond to “electric braking means”.

Next, operations and effects of the first embodiment will be described.
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.

In addition, 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 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 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 when 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 shifts to the two-wheel drive.

At this time, as shown in FIG. 9, since the electric motor 3 rotates inertially, if the vehicle stops before this inertial rotation stops, the motor sound is heard even though there is no vehicle running sound, which gives the passenger an uncomfortable feeling. End up.
For this reason, it is conceivable to apply a motor brake. However, since this motor brake causes heat generation of the inverter 9 and the electric motor 3, the inverter 9 and the electric motor 3 are overheated and deteriorated depending on the time for operating the motor brake. there is a possibility.

Therefore, when the wheel drive by the electric motor 3 is stopped and the transmission of power is interrupted by the electromagnetic clutch 11 ("Yes" in step S1), the inertial rotation of the motor stops when the wheel rotation stops. Thus, the motor brake is applied to the electric motor 3.
Specifically, as shown in FIG. 10, when the inertial rotation of the electric motor 3 is faster than the rotation of the rear wheels 1RL and 1RR, the rotation of the electric motor 3 is stopped even after the rotation of the wheels is stopped. It is presumed that inertial rotation continues ("Yes" in step S6), and the motor brake is applied to the electric motor 3 by a three-phase short circuit by the inverter 9 (step S11).

On the contrary, when the inertial rotation of the electric motor 3 is slower than the rotation of the rear wheels 1RL and 1RR, it is estimated that the inertial rotation of the electric motor 3 stops before the rotation of the wheels stops (step S6). Is "No"), the motor brake is stopped (step S4).
As a result, the inertial rotation of the electric motor 3 stops when the rotation of the wheels stops. Therefore, the noise when the electric motor 3 rotates inertially is reduced until the vehicle stops, and the uncomfortable feeling given to the occupant is eliminated. can do.

  Moreover, when the vehicle is accelerated in a two-wheel drive state as shown in FIG. 11 or when the vehicle is slowly decelerated as shown in FIG. 12, the inertial rotation of the electric motor 3 is stopped until the vehicle stops. In such a case, since the motor brake to the electric motor 3 can be inactivated, the temperature increase of the inverter 9 and the electric motor 3 due to the motor brake is suppressed to a minimum, and the inverter 9 and the electric motor 3 are overheated. Can be protected from deterioration. At this time, since the running sound of the vehicle is generated, the inertial rotation of the electric motor 3 does not give the passenger a sense of incongruity.

Incidentally, by stopping the inertial rotation of the electric motor 3 before the vehicle stops, it is possible to reliably prevent a shock when the electromagnetic clutch 11 is engaged when the vehicle tries to start again by four-wheel drive. it can.
Further, since it is estimated whether or not the inertial rotation of the electric motor 3 continues after the rotation of the wheel is stopped by comparing the rotation speeds of the wheel and the electric motor 3, this is easily and accurately estimated. be able to.

And when detecting the overheating tendency of the inverter 9 and the electric motor 3 while operating the motor brake, in order to protect the inverter 9 and the electric motor 3 from overheating deterioration, it is desirable to immediately stop the motor braking, The overheating tendency of the inverter 9 and the electric motor 3 caused by the motor brake is correlated with how much the motor rotation speed Nm is reduced.
Therefore, as shown in FIG. 13, when the motor rotation speed Nm decrease amount ΔN (= N ₀ −Nm) after the start of the motor brake is calculated, the decrease amount ΔN becomes equal to or greater than a predetermined value ΔN _1. ("Yes" at step S10), the inverter 9 and the electric motor 3 are determined to be overheated, and the motor brake is stopped (step S4).

Thereby, the overheating tendency of the inverter 9 and the electric motor 3 due to the motor brake can be immediately suppressed, and the inverter 9 and the electric motor 3 can be protected from overheating deterioration.
Further, when the motor rotation speed Nm immediately after the electromagnetic clutch 11 is disconnected as shown in FIG. 14 is less than a predetermined value Nm1, or as shown in FIG. 15, the motor rotation speed Nm is reduced to less than the predetermined value Nm1 by the motor brake. If this is the case (the determination in step S5 is “No”), it is determined that the motor sound is not so loud that the passenger feels uncomfortable, and the motor brake is stopped (step S4).

  As a result, the motor brake is not operated unnecessarily, and the heat generation of the inverter 9 and the electric motor 3 can be suppressed to the minimum, so that the inverter 9 and the electric motor 3 can be protected from deterioration due to heat generation. In particular, with the aim of improving vehicle start-up performance, a system that always runs with four-wheel drive in the low-speed range regardless of the presence of acceleration slip on the front wheels frequently switches from four-wheel drive to two-wheel drive. Therefore, the above effects stand out.

Further, since the inverter 9 and the electric motor 3 are detected to be overheated when the reduction amount ΔN of the motor rotation speed Nm after the start of the motor braking becomes equal to or greater than the predetermined value ΔN ₁ , the inverter 9 In addition, the tendency of overheating of the electric motor 3 can be detected easily and reliably.
In the first embodiment, it is determined in step S5 whether or not to operate the motor brake according to the motor rotation speed Nm. However, the present invention is not limited to this. The determination may be made according to both the vehicle speed V and the motor rotation speed Nm.

In the first embodiment, the motor brake is operated by a three-phase short circuit by the inverter 9, but the present invention is not limited to this, and a short circuit relay circuit may be provided separately.
Moreover, in said 1st Embodiment, although the motor brake is operated by the three-phase short circuit by the inverter 9, it is not limited to this, The brake torque of the reverse direction to inertial rotation of the electric motor 3 is generated. As a result, the electric motor 3 may be electrically braked.

  Moreover, in said 1st Embodiment, although the overheating tendency of the inverter 9 or the electric motor 3 is detected according to the reduction | decrease amount (DELTA) N of the motor rotation speed Nm after starting a motor brake, it is limited to this. It is not something. That is, the tendency of overheating of the inverter 9 and the electric motor 3 due to the motor brake has a correlation with how long the motor brake is operated, so when a predetermined time elapses after the motor brake is started, the inverter 9 and the electric motor 3 may be determined to be overheated, and the motor brake may be limited. Furthermore, when the inverter temperature or the motor temperature detected by the thermistor exceeds a predetermined value, it may be determined that the inverter 9 or the electric motor 3 tends to overheat, and the motor brake may be limited.

  Moreover, in said 1st Embodiment, although the overheating tendency of the inverter 9 and the electric motor 3 is detected, the motor brake is stopped, but after that, the overheating tendency of the inverter 9 and the electric motor 3 is eliminated. Once cooled, the motor brake may be resumed. In this case, it may be determined that the heating tendency has been eliminated when a predetermined time elapses after the motor brake is stopped, or when the inverter temperature and the motor temperature detected by the thermistor decrease to less than a predetermined value.

In the first embodiment described above, but calculates the first motor torque Tm1 in accordance with the front wheel slip rate [Delta] V _F, but is not limited thereto. In short, since the first motor torque Tm1 may be calculated according to the slip tendency of the front wheels 1FL and 1FR, for example, the first motor torque Tm1 may be calculated according to the wheel acceleration and the slip ratio of the front wheels 1FL and 1FR. .
In the first embodiment, the front wheels 1FL and 1FR are main drive wheels that are driven by the engine 2, and the rear wheels 1RL and 1RR are auxiliary drive wheels that can be driven by the electric motor 3. However, the present invention is not limited to this. Instead of this, the rear wheels 1RL and 1RR may be the main drive wheels, and the front wheels 1FL and 1FR may be the auxiliary drive wheels.

Further, in the first embodiment described above, a single motor type power train (power transmission system) that drives the rear wheels 1RL and 1RR with one electric motor 3 is adopted, but the present invention is not limited to this. Absent. For example, a two-motor system in which each wheel is driven by two electric motors, or a wheel-in motor system in which the motor itself is a driving wheel may be employed.
In the first embodiment described above, a hybrid system is adopted in which the front wheels are engine-driven and the rear wheels are motor-driven. However, the present invention is not limited to this. In addition, a series hybrid method, a parallel hybrid method, or a series / parallel hybrid (spirit hybrid) method may be adopted. Furthermore, the present invention may be applied to a pure electric vehicle (EV) not equipped with an internal combustion engine.
Moreover, in said 1st Embodiment, although the alternating current motor is used, you may use a direct current motor.
Furthermore, in the first embodiment, the present invention is applied to a four-wheeled vehicle, but may be applied to a two-wheeled vehicle, a three-wheeled vehicle, or a vehicle having five or more wheels.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In this second embodiment, when the inertial rotation of the electric motor 3 is lower than the rotation of the wheel, it is estimated that the inertial rotation of the electric motor 3 continues even after the wheel rotation stops when the deceleration is lower. is there.
Therefore, the calculation process of the second embodiment executed by the motor brake control processing unit 24F of FIG. 3 is changed from the process of step S6 of FIG. 8 to new steps S20 and S21 as shown in FIG. Except for this, the same processing as in the first embodiment described above is executed, so the corresponding parts are denoted by the same reference numerals, and detailed description thereof is omitted.

In step S20, a wheel deceleration rate αw is calculated according to the change amount of the average wheel speed of the wheels 1FL to 1RR. Although the wheel deceleration rate αw is calculated based on the wheel speed here, the present invention is not limited to this, and the vehicle body acceleration may be detected by an acceleration sensor and used.
In a succeeding step S21, it is determined whether or not the wheel deceleration rate αw is larger than the motor deceleration rate αm. The motor deceleration rate αm is a deceleration rate when the inertial rotation is performed without applying the motor brake, and is a value (for example, 0.2 G) determined by the motor specifications. Here, when the determination result is αw ≦ αm, it is determined that the inertial rotation of the electric motor 3 is stopped before the rotation of the wheel is stopped, and the process proceeds to step S2. On the other hand, when the determination result is αw> αm, it is determined that the inertial rotation of the electric motor 3 continues even after the rotation of the wheel is stopped, and the process proceeds to step S7.

Here, the processing of steps S20 and S21 corresponds to “rotation estimation means”.
According to the second embodiment, as shown in FIG. 17, when the inertial rotation of the electric motor 3 is lower than the rotation of the wheel, when the deceleration is lower, the rotation of the electric motor 3 is stopped even after the wheel rotation is stopped. It is presumed that inertial rotation will continue ("Yes" in step S21), and the motor brake is applied to the electric motor 3 by a three-phase short circuit by the inverter 9 (step S11).

On the contrary, when the inertial rotation of the electric motor 3 is higher than the rotation of the wheel, it is estimated that the inertial rotation of the electric motor 3 stops before the wheel rotation stops (the determination in step S21 is “ No "), the motor brake is stopped (step S4).
Thereby, since the inertial rotation of the electric motor 3 can be stopped before the rotation of the wheel stops, the sound when the electric motor 3 rotates inertially is reduced until the vehicle stops, and the uncomfortable feeling given to the occupant is given. Can be resolved.

  Moreover, when the inertial rotation of the electric motor 3 stops before the vehicle stops, such as when the vehicle slowly decelerates (for example, the deceleration is 0.1 G), the motor brake to the electric motor 3 is not activated. Therefore, the temperature rise of the inverter 9 and the electric motor 3 due to the motor brake can be suppressed to the minimum, and the inverter 9 and the electric motor 3 can be protected from overheating deterioration. At this time, since the running sound of the vehicle is generated, the inertial rotation of the electric motor 3 does not give the passenger a sense of incongruity.

Further, since it is estimated whether or not the inertial rotation of the electric motor 3 continues even after the rotation of the wheel is stopped by comparing the deceleration between the wheel and the electric motor 3, this is easily and accurately estimated. be able to.
Other functions and effects are the same as those of the first embodiment described above.
In the first and second embodiments described above, the method for estimating whether or not the inertial rotation of the electric motor 3 continues even after the rotation of the wheels is stopped is different, but the first and second embodiments are combined. May be.

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 target motor torque calculation part 24A. It is a block diagram of power generation control part 24C. 4 is a block diagram of a control processing unit 43. FIG. It is a block diagram of motor control part 24D. It is a flowchart which shows the arithmetic processing of 1st Embodiment performed by the motor brake control part 24F. It is a time chart explaining operation | movement of a prior art. It is a time chart explaining the effect of 1st Embodiment. It is a time chart explaining operation | movement of this invention (when a vehicle accelerates in the state of two-wheel drive). It is a time chart explaining operation | movement of this invention (when a vehicle decelerates gently). 6 is a time chart for explaining the operation of the present invention (when the motor rotation speed Nm is decreased by a predetermined value ΔN ₁ or more by the motor brake). 6 is a time chart for explaining the operation of the present invention (when the motor rotation speed Nm after the clutch is turned off is less than a predetermined value Nm1). It is a time chart explaining operation | movement of this invention (when the motor rotation speed Nm becomes less than predetermined value Nm1 by a motor brake). It is a flowchart which shows the arithmetic processing of 2nd Embodiment performed by the motor brake control part 24F. It is a time chart explaining the effect of 2nd Embodiment.

Explanation of symbols

1FL, 1FR Front wheel 1RL, 1RR Rear wheel 2 Engine 3 Electric motor 4 Automatic transmission 5 Differential gear 6 V belt 7 Generator 8 Power cable 9 Inverter 10 Reducer 10
DESCRIPTION OF SYMBOLS 11 Electromagnetic clutch 12 Differential gear 20 Engine controller 21 Acceleration sensor 22 Throttle valve 23 Throttle motor 24 4WD controller 25 14V battery 26 Junction box 24A Target motor torque calculating part 24B Motor required power calculating part 24C Electric power generation control part 24D Motor control part 24E Clutch control 24F Motor brake control unit

Claims (6)

In a vehicle drive control device comprising: an electric motor capable of driving a wheel; and an interrupting mechanism capable of interrupting transmission of power between the electric motor and the wheel.
When driving of the wheel by the electric motor is stopped and transmission of power is interrupted by the intermittent mechanism, electric braking is applied to the electric motor so that the inertial rotation of the electric motor stops when the rotation of the wheel stops. A vehicle drive control device comprising an electric braking means for applying. Rotation estimation means for estimating whether or not inertial rotation of the motor continues even after rotation of the wheel is stopped when driving of the wheel by the electric motor is stopped and transmission of power is interrupted by the intermittent mechanism; Prepared,
2. The electric braking device according to claim 1, wherein the electric braking device applies electric braking to the electric motor when it is estimated that inertial rotation of the electric motor continues after the rotation of the wheel is stopped by the rotation estimating device. The vehicle drive control device described.   The rotation estimation means estimates that inertial rotation of the motor continues even after rotation of the wheel is stopped when the inertial rotation of the motor is faster than the rotation of the wheel. The vehicle drive control device according to claim 2.   The rotation estimation means estimates that the inertial rotation of the electric motor continues even after the rotation of the wheel stops when the inertial rotation of the electric motor is slower than the rotation of the wheel. The vehicle drive control device according to claim 2 or 3.   The vehicle drive control device according to any one of claims 1 to 4, wherein the electric braking means limits electric braking to the electric motor when detecting an overheating tendency of the electric motor.   The vehicle drive control according to any one of claims 1 to 5, wherein the electric braking means prohibits electric braking to the electric motor when a rotation speed of the electric motor is a predetermined value or less. apparatus.

Images