JP2006214538A - Generator output control device in electric motor type four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a system by performing the generator output control of an electric motor type four-wheel drive vehicle by a generator speed control through the change of a gear shift schedule without relying on a field current control. <P>SOLUTION: While the operating switch of a traction control device (TCS) is determined to be On in S21 and a target generation load torque Th is determined to be positive (generation is requested) in S23, a gear shift schedule for generator output control is selected as a gear shift schedule for an automatic transmission in S26. The gear shift schedule changes the speed of a generator so that a requested power after the change can be provided at a generator target operation point after the change while the field current instruction of the generator is maintained unchanged when the generator target operation point which is the combination of the target armature current of the generator for generating the requested power and a target generating voltage is changed by the variation of the requested power. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric motor type four-wheel drive vehicle in which one of front and rear wheels is driven by an automatic transmission by a main power source such as an internal combustion engine (engine) and the other wheel is driven by power from an electric motor. In particular, the present invention relates to an output control technique for a generator that is driven by a main power source and supplies electric power to an electric motor.

  In addition to main drive wheels driven via an automatic transmission by power from a main power source such as an internal combustion engine (engine), the generated power of a generator coupled to a drive system between the main power source and the automatic transmission Conventionally, as an electric motor type four-wheel drive vehicle including an electric motor drive wheel driven by power from an electric motor that responds to the above, there is a conventional one disclosed in Patent Document 1, for example.

In this vehicle, the front two wheels (or the rear two wheels) are driven by an engine, the rear two wheels (or the front two wheels) can be driven by an electric motor via a clutch, and the vehicle is dedicated to four-wheel drive power generation coupled to the engine. The electric motor is directly driven by the power from the machine.
In brief, the engine drive wheels are likely to drive slip, or when the engine slips, the generator is loaded by the surplus torque of the engine to generate power, and the electric motor is driven by this generated power and fastened at this time. By transmitting the power from the electric motor to the electric motor drive wheels via the clutch, motor four-wheel drive is enabled.

Note that the clutch is basically released when it is not driven by four wheels, so that the electric motor drive wheels do not drag the electric motor to avoid deterioration of fuel consumption. Since the drive wheels are likely to cause drive slip and are preferably in the four-wheel drive state, the clutch is kept in the engaged state.
When starting, a load corresponding to the amount of depression of the accelerator pedal is applied to the generator to generate power, and the electric motor is driven by the electric power to start in a four-wheel drive state.

By the way, for main drive wheels driven by power from a main power source such as an internal combustion engine (engine), the traction control device changes the shift schedule of the automatic transmission at the time of acceleration slip, and the driving force of the main drive wheels In some cases, the acceleration slip of the main drive wheel is suppressed by lowering the speed.
When such a trunk control device is operated, the automatic transmission shifts to the high gear ratio, so that the generated power tends to be insufficient due to a decrease in the rotational speed of the generator driven by the main power source. The driving force of the wheels is also insufficient, and a normal four-wheel drive state cannot be realized.
Therefore, as described in Patent Document 2, the operation of the traction control device is prohibited during acceleration slip of the main drive wheel to eliminate the tendency of the generator to generate insufficient power, thereby giving priority to the four-wheel drive over the traction control. Such a technique has been conventionally proposed.
JP 2002-218605 A JP 2004-100718 A

  However, if the operation of the trunk control device is prohibited as described above, the following problems occur.

First, generator output control generally performed will be described.
FIG. 7 shows a generator output characteristic representing a change characteristic of the generated power P that can be output by a combination of the armature current Ia and the generated voltage V when the generator rotational speed Nh is a certain rotational speed A. The lines are exemplified by P1 and P2, and the generator output characteristic line changes from P1 to P2 as the generator field current Ifh increases.

As shown in FIG. 7, when the generator target operating point that is a combination of the target armature current Ia1 and the target generator voltage V1 for generating the required power is X1, the generator output characteristic line is The field current is supplied to the generator so as to be P1, and thereby the generated power corresponding to the generator target operating point X1 is obtained and the required power is realized.
Then, the target armature current Ia of the generator for generating this by the change in the required power changes from Ia1 to Ia2, the target generated voltage V changes from V1 to V2, and the generator that is a combination of these When the target operating point moves from X1 to X2, the generator field current is changed so that the generator output characteristic line changes from P1 to P2, thereby obtaining the generated power corresponding to the generator target operating point X2. Realize the required power.

  However, in general generator output control through field current control as described above, an extra field current control logic and control system is required as described in Patent Document 2 above. The problem of becoming high arises.

On the other hand, if the generator rotational speed Nh is changed from A to B described above even when the command value of the field current Ifh is maintained at the value obtained by the generator output characteristic line P1 in FIG. Even when Nh changes, the generator output characteristic line changes from P1 in FIG. 7 to P3 in FIG. 8, and becomes a characteristic line P3 including the same generator target operating point X2 as X2 in FIG.
Therefore, even if the command value of the field current Ifh is kept constant, the generated power corresponding to the generator target operating point X2 can be obtained and the required power can be achieved simply by changing the generator speed Nh from A to B. This eliminates the need for a field current control logic and control system, and eliminates the above-mentioned problems associated with high costs.

However, prohibiting the operation of the trunk control device as described in Patent Document 2 cannot change the speed change schedule necessary to change the generator rotational speed Nh as described above.
As described above, the generator generates the required power by changing the generator speed Nh while keeping the field current constant, so that the field current control logic and control system are not required and the cost is reduced. It is impossible to adopt a technique of realizing problem solving related to high.

  In view of the above circumstances, the present invention utilizes the shift schedule changing function without prohibiting the operation of the trunk control device, and generates power while keeping the field current of the generator constant as described above. The generator output control of an inexpensive electric motor type four-wheel drive vehicle that eliminates the need for field current control logic and control system by changing the machine speed Nh so that the generator generates the required power. An object is to provide an apparatus.

For this purpose, a generator output control device for an electric motor type four-wheel drive vehicle according to the present invention comprises:
Main drive wheels driven via an automatic transmission by power from a main power source;
An electric motor drive wheel driven by power from an electric motor that responds to power generated by a generator coupled to a drive system between the main power source and the automatic transmission;
In the electric motor type four-wheel drive vehicle having a traction control device that suppresses the acceleration slip of the main drive wheel by lowering the driving force of the main drive wheel by changing the shift schedule of the automatic transmission,
When the generator target operating point, which is a combination of the target armature current and the target generated voltage of the generator for generating the required power, is changed by the change in the required power during the operation of the trunk control device, The generator rotation speed control means for changing the shift schedule so as to change the rotation speed of the generator so as to obtain the changed required power at the changed generator target operating point while keeping the field current command unchanged. Is provided.

According to the generator output control device of the present invention, when the generator target operating point for generating the required power changes due to the change in the required power, the speed change is performed while keeping the field current command of the generator unchanged. By changing the number of revolutions of the generator so that the required power after the change can be obtained at the target operation point after the change by changing the schedule,
Since field current control of the generator is not required for the output control of the generator, the field current control logic and control system are unnecessary, and the generator output control device for the electric motor type four-wheel drive vehicle is inexpensive. Can be a thing.
Since the shift schedule is changed during the operation of the traction control device, the above-described effects can be achieved by utilizing the shift schedule changing operation of the traction control device.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 schematically shows a drive system of an electric motor type four-wheel drive vehicle equipped with a generator output control device according to an embodiment of the present invention. In this embodiment, this vehicle is mainly composed of left and right front wheels 1L and 1R. A front engine / front wheel drive vehicle (F / F vehicle) driven by an engine (internal combustion engine) 2 as a power source is used as a base vehicle, and the left and right rear wheels 3L and 3R are electric motors as required. It is assumed that the vehicle can be driven by a so-called motor four-wheel drive vehicle.

  The engine 2 is drivably coupled to the left and right front wheels (main drive wheels) 1L and 1R via a transaxle in which an automatic transmission (here, continuously variable transmission) 5 and a differential gear device 6 are formed as an integral unit. Is transmitted to the left and right front wheels 1L and 1R via the automatic transmission 5 and the differential gear device 6, and is used for traveling of the vehicle.

Next, the rear wheel drive system by the electric motor 4 will be described. This is basically the same as that in the motor four-wheel drive vehicle described in Patent Document 1.
That is, a dedicated generator 8 that is driven via the endless belt 7 by a part of the output torque of the engine 2 is provided, and this generator 8 is rotated at a rotational speed obtained by multiplying the rotational speed of the engine 2 by the belt pulley ratio. The power generation load corresponding to the command value related to the constant field current Ifh commanded by the four-wheel drive controller 9 is applied to the engine 2 to generate power corresponding to the load torque.
However, this generated power is determined in accordance with the number of revolutions of the generator 8 controlled through the shift schedule change as described above, as described above.

The electric power generated by the generator 8 is supplied to the rear wheel drive motor 4 through the relay 11 by the power line 10.
The relay 11 can also be used in response to a command from the controller 9 to shut off the power line 10 when the generator 8 becomes poorly controlled, or when the controller 9 does not require rear wheel drive and the controller 9 does not apply a power generation load to the generator 8. Since there is some power generation by the permanent magnet, the power line 10 is cut off so as not to be supplied to the motor 4.

  The drive shaft of the rear wheel drive motor 4 is coupled to the differential gear device 14 of the rear wheels (electric motor drive wheels) 3L and 3R via the speed reducer 12 and the clutch 13 incorporated therein, and the output torque of the motor 4 is If the gear 13 is increased by the reduction gear 12 and the clutch 13 is engaged, the increased torque is distributed and output to the left and right rear wheels 3L and 3R by the differential gear device 14.

The four-wheel drive controller 9 also controls the engagement / release of the clutch 13 and the rotation direction / drive torque of the electric motor 4.
In controlling the electric motor 4, the controller 9 controls the motor driving torque by adjusting the field current Ifm to the electric motor 4, and controls the motor rotation direction by the direction of the field current Ifm.

In order to perform the above-described control of the motor 4, the generator 8, the relay 11, and the clutch 13, in addition to inputting the signal from the four-wheel drive switch 21 to the four-wheel drive controller 9,
Signals from the wheel speed sensor group 22 for individually detecting the wheel speeds (front wheel speeds) V _WFL and V _WFR of the left and right front wheels 1L and 1R and the wheel speeds (rear wheel speeds) V _WRL and V _WRR of the left and right rear wheels 3L and 3R When,
A signal from a motor rotation sensor 23 for detecting the rotational speed Nm of the rear wheel drive motor 4;
A signal from the inhibitor switch 24 for detecting whether the selection range RNG (travel direction command by the driver) of the automatic transmission 5 is the forward (D) range or the reverse (R) range;
A signal from the accelerator opening sensor 25 for detecting the accelerator pedal depression amount APO is input.

The four-wheel drive controller 9 determines whether the four-wheel drive is necessary and automatically performs the motor four-wheel drive as described below while the driver turns on the four-wheel drive switch 21.
While the driver is turning off the four-wheel drive switch 21, the two-wheel drive by only the engine drive of the front two wheels is continuously performed.

A transmission controller 26 is based on a shift schedule selected by the four-wheel drive controller 9 as will be described later. Usually, the vehicle speed VSP determined from the rear wheel speeds V _WRL and V _WRR read via the four-wheel drive controller 9. Similarly, the transmission input rotational speed (engine rotational speed) to be targeted is obtained from the accelerator opening APO read through the four-wheel drive controller 9, and an automatic transmission ( The continuously variable transmission) 5 is controlled to change speed.
When generator output control is required, the transmission input rotation speed (engine rotation speed) to be targeted is obtained based on a shift schedule for generator output control, which will be described later, and automatic transmission is performed so that the corresponding gear ratio is obtained. It is assumed that the machine (continuously variable transmission) 5 is controlled to shift.

In addition to performing the above-described shift control, the transmission controller 26 reads the wheel speeds (front wheel speeds) V _WFL and V _WFR and the left and right rear wheels 3L and 3R of the left and right front wheels 1L and 1R read via the four-wheel drive controller 9. Acceleration slip of the front wheels 1L, 1R is detected by comparing the average rear wheel speed and the average front wheel speed on the basis of the wheel speeds (rear wheel speeds) V _WRL , V _WRR , and high-side gear ratio trends when front wheel acceleration slips occur The automatic transmission 5 shift schedule is changed to the trunk schedule control (TCS) shift schedule to reduce the torque from the engine 2 to the left and right front wheels 1L, 1R, thereby suppressing the acceleration slip of the front wheels. Control shall also be performed.
Therefore, the transmission controller 26 also constitutes a traction control device and supplies a signal indicating that the traction control is being executed to the four-wheel drive controller 9.

Hereinafter, basic four-wheel drive control performed by the controller 9 will be described.
First, the surplus torque of the engine 2 that causes the drive (acceleration) slip of the front wheels 1L and 1R, which are the main drive wheels (engine drive wheels), is calculated by the processing shown in FIG.
In step S1, from the average front wheel speed Vwf that can be obtained from the front wheel speeds V _WFL and V _WFR detected by the wheel speed sensor group 22, the after average that can be obtained from the rear wheel speeds V _WRL and V _WRR that are also detected by the wheel speed sensor group 22 The wheel speed Vwr is subtracted to obtain the acceleration slip amount ΔVf of the left and right front wheels 1L and 1R which are the main drive wheels.

In the next step S2, it is determined whether or not an acceleration slip has occurred depending on whether or not the acceleration slip amount ΔVf of the left and right front wheels 1L and 1R is a predetermined value, for example, 3 km / h or more.
When it is determined that the acceleration slip amount ΔVf is less than 3 km / h, the control is terminated as it is because no acceleration slip has occurred and there is no surplus of engine output.

When the acceleration slip is determined in step S2 that the acceleration slip amount ΔVf is 3 km / h or more, it is necessary to suppress the excess torque of the engine that generates the acceleration slip of the front wheels 1L and 1R, that is, the acceleration slip in step S3. The absorption torque T (ΔVf) is calculated by T (ΔVf) = K1 × ΔVf.
K1 is a gain obtained through experiments or the like.

In the next step S4, the current load torque Tg of the generator 8 is obtained. In step S5, the target generator load of the generator 8 is calculated by adding the current generator load torque Tg and the surplus torque T (ΔVf). Find the torque Th.
In step S6, the wheel speed _{V WFL, V WFR, V WRL} , vehicle speed VSP is capable determined from _{V WRR,} motor overspeed speed (for example, a lower limit of the speed range for over-rotating the motor 4 when engagement of the clutch 13 Check if it is less than 30km / h).

If the vehicle speed is greater than or equal to the motor overspeed vehicle speed, the motor 4 is overrotated and the durability of the motor 4 is reduced. Therefore, the control is terminated as is so that the four-wheel drive is not performed. In S7, the maximum load torque Thmax of the generator 8 is obtained.
Next, in step S8, it is checked whether or not the target power generation load torque Th of the generator 8 is equal to or greater than the maximum load torque Thmax. If so, in step S9, Th = Thmax is set to Thmax, which is a limit that can achieve the target power generation load torque Th. If Th <Thmax, the control is terminated and the target power generation load torque Th is set to the value obtained in step S5.

  In FIG. 2, the method for obtaining the target power generation load torque Th of the generator 8 is described only when the engine drive wheels 1L and 1R generate an acceleration slip. However, the engine drive wheels 1L and 1R may be accelerated and slipped. In some cases or even when the vehicle is in a low speed state below a predetermined value, the target power generation load torque Th of the generator 8 is obtained according to the driving situation in order to realize the motor four-wheel drive.

The controller 9 controls the generator 8 and the motor 4 by the control program of FIG. 3 based on the target power generation load torque Th of the generator 8 obtained as described above.
In step S11, it is checked whether or not there is a power generation request depending on whether or not the target power generation load torque Th of the generator 8 is positive.
If there is no power generation request, the control is terminated so that the power generation load of the generator 8 is not applied to the engine 2 and the clutch 13 is in a released state.
If there is a power generation request, in step S12, the target motor field current Ifm is calculated from the motor rotation speed Nm based on the planned map, and this is commanded to the motor 4.
Although not shown, at the same time, when the input / output rotational speeds of the clutch 13 coincide, the clutch 13 is engaged so that the rotation of the motor 4 can be transmitted by the rear wheels 3L and 3R.

Here, as shown in step S12, the target motor field current Ifm with respect to the rotational speed Nm of the motor 4 is set to a constant predetermined current value when the motor rotational speed Nm is equal to or smaller than the predetermined rotational speed, and the motor rotational speed beyond that If the number exceeds the number, the field current Ifm of the motor 4 is reduced by a known field weakening control method.
The reason for this is that when the motor 4 rotates at a high speed, the motor torque decreases due to the increase of the motor back electromotive force E. Therefore, when the motor rotation speed Nm exceeds a predetermined value, the field current Ifm of the motor 4 is decreased and reversed. This is to reduce the electromotive voltage E to increase the current flowing through the motor 4 so that the required motor torque Tm can be obtained.

Next, in step S13, the back electromotive force E of the motor 4 is calculated from the target motor field current Ifm obtained as described above and the rotational speed Nm of the motor 4 based on a predetermined map.
Further, in step S14, a corresponding target motor torque Tm is calculated based on the power generation load torque Th, and in step S15, a target armature current Ia which is a function of the target motor torque Tm and the target motor field current Ifm is calculated. Calculate
Thereafter, in step S16, the target voltage V of the generator 8 is obtained from the target armature current Ia, the total resistance R, and the counter electromotive voltage E by calculation of V = Ia × R + E.

  Further, the controller 9 executes the control program of FIG. 4 based on the target voltage V of the generator 8 obtained as described above to select the shift schedule for generator output control, and also executes the control program of FIG. Then, the normal shift schedule or the trunk control (TCS) shift schedule is selected as follows, and the selected shift schedule is instructed to the transmission controller 26.

In step S21 of FIG. 4, the trunk control device (TCS) is in operation (TCS) to determine whether or not the generator speed control for generator output control can be performed by changing the shift schedule by the trunk control. Check if the switch is ON) or not.
While the TCS switch is OFF, that is, when the operation of the Traction Control Device (TCS) is not required, the generator rotation speed control for the generator output control described above is changed by the trunkion control. Since it cannot be performed by changing the schedule, a normal shift schedule as usual is selected as a shift schedule used for the shift control of the automatic transmission 5 and commanded to the transmission controller 26 in step S22.
At this time, the transmission controller 26 obtains the target input rotational speed (target engine rotational speed) from the vehicle speed VSP and the accelerator opening APO based on the normal transmission schedule, and the transmission input rotational speed (engine rotational speed) is the target input. The automatic transmission 5 is shift-controlled so that the rotation speed (target engine rotation speed) is reached.

While it is determined in step S21 that the operation of the trunk control device (TCS) is requested (TCS switch is ON), in step S23, the generator is determined depending on whether or not the target power generation load torque Th is positive. It is determined whether power generation by 8 is requested.
If power generation is not required, the generator speed control for generator output control described above is unnecessary, and the shift used for the shift control of the automatic transmission 5 in response to the TCS request determination in step S21. As a schedule, a transmission schedule for the trunk control (TCS) that suppresses acceleration slip of the front wheels 1L and 1R is selected and commanded to the transmission controller 26.
At this time, the transmission controller 26 obtains the target input rotational speed (target engine rotational speed) from the vehicle speed VSP and the accelerator opening APO based on the TCS shift schedule, and the transmission input rotational speed (engine rotational speed) is the target rotational speed. By performing shift control of the automatic transmission 5 so as to be the input rotational speed (target engine rotational speed), the driving torque of the front wheels 1L and 1R is reduced to suppress the acceleration slip.
After selecting the normal shift schedule or the TCS shift schedule in step S22 or step S24, a command for prohibiting generator speed control (generator output control) for generator output control is issued in step S25.

If it is determined in step S21 that the TCS switch is ON and it is determined in step S23 that Th> 0 (power generation is being requested), the generator speed control for generator output control described above is possible. In addition, since it is necessary, in step S26, a shift schedule for generator output control, which will be described later, is selected as a shift schedule used for shift control of the automatic transmission 5, and a transmission controller 26 is commanded.
Therefore, step S26 corresponds to the generator rotational speed control means in the present invention.
After selecting the generator output control shift schedule in step S26, in step S27, a command is issued to the effect that generator speed control (generator output control) for generator output control is possible.

  The shift schedule for generator output control in step S26 will be described with reference to the example shown in FIGS. 7 and 8. The target armature current Ia = Ia1 and the target generated voltage V = V1 of the generator 8 for generating the required power. When the generator target operating point X1 is changed to X2 shown in FIG. 7 and FIG. 8 due to the change in the required power, the field current (Ifh) command of the generator 8 remains unchanged and the changed The speed change schedule is such that the rotational speed Nh of the generator 8 is changed from A in FIG. 7 to B in FIG. 8 so that the required power after change is obtained at the generator target operating point X2.

  In the case of this embodiment, such a generator output control shift schedule is shown in FIG. 6 for each accelerator opening APO as illustrated for the case where the accelerator opening APO (engine load state) is 2/8 to 4/8. The target engine speed Ne (target transmission input speed) of the normal normal shift schedule defined as the target engine speed Ne (target transmission input speed) with respect to the vehicle speed VSP is set to the target generated voltage V (step of FIG. 3). It is assumed that the generator output control speed change schedule is corrected so that the change (A → B) of the generator rotational speed Nh described above is caused in accordance with the change (change in required power) in S16.

  Therefore, in this embodiment, the generator output control shift schedule map III for the accelerator output control when the accelerator opening APO (engine load state) shown in FIG. 6 is 2/8 to 4/8 is shown in FIG. In addition, although not shown, the shift schedule map I for generator output control when the accelerator opening APO (engine load state) is less than 1/8, the accelerator opening APO (engine load state) is 1 / Shift schedule map II for generator output control when 8 to 2/8, shift schedule map IV for generator output control when accelerator opening APO (engine load state) is 4/8 to 6/8, When the accelerator opening APO (engine load state) is 6/8 to 7/8, the shift schedule map V for generator output control, and when the accelerator opening APO (engine load state) is 7/8 or more Shift schedule for generator output control Has a map VI.

Therefore, the generator output control shift schedule in step S26 is selected by the control program shown in FIG.
In steps S31 to S35 of FIG. 5, it is determined in which of the above-mentioned areas the accelerator opening APO belongs, that is, whether the accelerator opening APO is less than 1/8 or 1/8 to 2/8. It is checked whether it is 2/8 to 4/8, 4/8 to 6/8, 6/8 to 7/8, or 7/8 or more.

In accordance with these determination results, if the accelerator opening APO is less than 1/8, the generator output control shift schedule map I is selected and commanded to the transmission controller 26 in step S36,
If the accelerator opening APO is 1/8 to 2/8, the generator output control shift schedule map II is selected in step S37 and commanded to the transmission controller 26.
If the accelerator opening APO is 2/8 to 4/8, the above-mentioned generator output control shift schedule map III is selected and commanded to the transmission controller 26 in step S38,
If the accelerator opening APO is 4/8 to 6/8, in step S39, the generator output control shift schedule map IV is selected and commanded to the transmission controller 26.
If the accelerator opening APO is 6/8 to 7/8, in step S40, the generator output control shift schedule map V is selected and commanded to the transmission controller 26.
If the accelerator opening APO is 7/8 or more, the generator output control shift schedule map VI is selected and commanded to the transmission controller 26 in step S41.

  The transmission controller 26 determines the vehicle speed VSP and the target generated voltage based on the generator output control shift schedule maps I to VI (only the map III is illustrated in FIG. 6) selected according to the accelerator opening APO as described above. A target input rotational speed (target engine rotational speed) is obtained from V, and the automatic transmission 5 is shift-controlled so that the transmission input rotational speed (engine rotational speed) becomes the target input rotational speed (target engine rotational speed).

With the shift control based on the generator output control shift schedule maps I to VI, the rotational speed Nh of the generator 8 driven by the engine is changed according to the change in the target generated voltage V (required power),
The case where the generator target operating point corresponding to the required power has moved from X1 in FIG. 7 to X2 in FIGS. 7 and 8 will be described. The rotational speed Nh of the generator 8 is Nh = A in FIG. 7 to Nh in FIG. = B will be changed.
On the other hand, the field current (Ifh) command value of the generator 8 is maintained at such a value that the generator output characteristic line becomes P1 in FIG. 7 under Nh = A, as described above with reference to FIG.

Therefore, the output characteristic line of the generator 8 is changed from that shown by P1 in FIG. 7 by changing the generator rotational speed Nh from A to B, and the generator target operating point X2 as shown by P3 in FIG. It will pass.
Therefore, even if the command value of the field current Ifh is kept constant, the generated power corresponding to the changed generator target operating point X2 is obtained and requested by the change in the generator speed Nh from A to B. Electric power can be realized.
By the way, in the generator output control for realizing the required power in this way, since the control is performed by the rotational speed control of the generator 8 through the change of the shift schedule, the field current control of the generator 8 is performed in this control. This is unnecessary, and can eliminate the need for a field current control logic and control system, thereby reducing the generator output control device for an electric motor type four-wheel drive vehicle.

Since the generator output control shift schedule maps I to VI are selected while determining that the traction control device (TCS) is operating in step S21,
Selection of the shift schedule map can be realized by changing the shift schedule in the trunk control device.

  As described above with reference to FIG. 6, the generator output control shift schedule maps I to VI are represented as normal normal transmission input speed Ne with respect to the vehicle speed VSP for each accelerator opening APO (engine load state). Shift schedule I for generator output control obtained by correcting the target transmission input rotation speed Ne of the shift schedule so as to cause the change in the generator rotation speed according to the change in the target generated voltage V (required power). ~ VI is prepared in advance, and the generator output control shift schedule I ~ VI corresponding to the accelerator opening APO (engine load state) is selected and commanded, so the calculation load can be reduced by mapping the shift schedule Can do.

The field current Ifh of the generator 8 can be covered by its own generated power when the engine speed Ne is high, and the generator 8 can operate by self-excitation, but the engine speed Ne is low. In this case, the field current Ifh of the generator 8 cannot be covered from the power generated by itself, and the generator 8 operates by separate excitation while obtaining the field current Ifh from the power from the battery.
Accordingly, in the generator output control shift schedule maps I to VI, as representatively shown in FIG. 6, the low engine rotation region is the generator's other excitation region, and the high engine rotation region is the generator's self-excitation region. Needless to say.

It is a basic diagram which shows the drive control system of the electric motor type four-wheel drive vehicle provided with the generator output control apparatus which becomes one Example of this invention. It is a flowchart which shows the engine surplus torque calculation program which the four-wheel drive controller in the drive control system of the motor four-wheel drive vehicle performs. It is a flowchart which shows the generator and motor control program which the same 4 wheel drive controller performs. It is a flowchart which shows the shift schedule selection program which the four-wheel drive controller performs. It is a flowchart which shows the subroutine regarding the determination process of the shift schedule for generator output control in the shift schedule selection program. It is a three-dimensional map figure which illustrates the shift schedule for generator output control when an accelerator opening is 2 / 8-4 / 8. It is a generator output characteristic diagram used for explanation of operation in the case of performing generator output control when the target operating point of a generator moves from X1 to X2 by field current control as before. FIG. 8 is a generator output characteristic diagram used for explanation of the operation when the generator output control is executed by the generator rotational speed control when the target operating point of the generator moves from X1 to X2 as in FIG. .

Explanation of symbols

1L front left wheel (main drive wheel)
1R right front wheel (main drive wheel)
2 Engine (Main power source)
3L front left wheel (electric motor drive wheel)
3R front right wheel (electric motor drive wheel)
4 Rear wheel drive motor (electric motor)
5 Continuously variable transmission (automatic transmission)
6 Differential gear device 7 Endless belt 8 Generator 9 Four-wheel drive controller
10 Power line
11 Relay
12 Reducer
13 Clutch
14 Differential gear unit
21 Four-wheel drive switch
22 Wheel speed sensors
23 Motor rotation sensor
24 Inhibitor switch
25 Accelerator position sensor
26 Transmission controller (Traction control device)

Claims (2)

Main drive wheels driven via an automatic transmission by power from a main power source;
An electric motor drive wheel driven by power from an electric motor that responds to power generated by a generator coupled to a drive system between the main power source and the automatic transmission;
In the electric motor type four-wheel drive vehicle having a traction control device that suppresses the acceleration slip of the main drive wheel by lowering the driving force of the main drive wheel by changing the shift schedule of the automatic transmission,
When the generator target operating point, which is a combination of the target armature current and the target generated voltage of the generator for generating the required power, is changed by the change in the required power during the operation of the trunk control device, The generator rotation speed control means for changing the shift schedule so as to change the rotation speed of the generator so as to obtain the changed required power at the changed generator target operating point while keeping the field current command unchanged. A generator output control device for an electric motor type four-wheel drive vehicle. The generator output control device for an electric motor type four-wheel drive vehicle according to claim 1,
The generator rotational speed control means converts a target transmission input rotational speed of a normal transmission schedule expressed as a target transmission input rotational speed with respect to a vehicle speed for each load state of the main power source into a change in the target generated voltage. A generator output control shift schedule obtained by correcting the change of the generator rotational speed so as to occur, and selecting a generator output control shift schedule according to the load state of the main power source A generator output control device for an electric motor type four-wheel drive vehicle.

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