JP2004088872A - Drive controller for motor four-wheel drive car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive controller for a motor four-wheel drive car which can improve a travel feeling by the reduction of a sense of physical disorder to an occupant at start, while securing reliability on the durability of a motor drive system. <P>SOLUTION: In a motor four-wheel drive car, one drive shaft is driven by an engine 2 and the other drive shaft is driven by a motor 4 driven by electric energy generated by the engine 2. The four-wheel drive car is provided with a motor driving means for driving the motor 4 so as to generate a driving force geared to the opening of an accelerator, and a clutch 12 capable of connecting/disconnecting the motor 4 and a drive wheel with each other. Further, the car is equipped with a connecting/disconnecting mechanism control means which disconnects the clutch 12 when it does not drive the motor 4 by motor drive control, and a backlash closing control means which connects the clutch 12 immediately before an accelerator is stepped down at the start of a vehicle and gives initial torque to the motor 4 by the amount of closing the backlash of the motor drive system. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drive control device for a four-wheel drive motor vehicle that drives one of the front and rear wheels with engine driving force and drives the other of the front and rear wheels using energy generated by the engine. Belongs to.
[0002]
[Prior art]
BACKGROUND ART Conventionally, as a motor power transmission device of a motor four-wheel drive vehicle, for example, a motor power transmission device described in JP-A-2001-287550 is known.
[0003]
This conventional publication describes a motor power transmission device that drives a rear wheel using an energy generated by an engine that drives a front wheel.
[0004]
[Problems to be solved by the invention]
However, in a conventional motor power transmission device of a motor four-wheel drive vehicle, the motor is stopped under predetermined conditions such as when the vehicle is stopped or coasting, and the clutch is released to separate the drive wheel from the motor. Therefore, the reduction gear from the motor to the clutch will have backlash, and if the clutch is engaged and the motor is driven in this state, the inertia of the drive system will idle for the amount of backlash and the backlash will be clogged. , Transmitting torque. For this reason, especially when the backlash is reduced at the time of starting, an impact torque is generated, giving a sense of incongruity due to a change in longitudinal acceleration or abnormal noise, and a problem that the life of the drive system is shortened.
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to improve the driving feeling by reducing the discomfort to the occupant at the time of starting while ensuring the durability reliability of the motor drive system. It is an object to provide a drive control device for a wheel drive vehicle.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a motor four-wheel drive vehicle in which one drive shaft is driven by an engine and the other drive shaft is driven by an electric motor driven by electric energy generated by the engine. An electric motor drive control means for driving and controlling an electric motor so as to generate a driving force corresponding to an accelerator opening, and a connecting / disconnecting mechanism capable of connecting / disconnecting between the electric motor and driving wheels. When the electric motor is not driven by the control means, the connection / disconnection mechanism control means for disconnecting the connection / disconnection mechanism is connected to the connection / disconnection mechanism immediately before the accelerator is depressed when starting the vehicle, and the amount of play in the motor drive system is reduced. Backlash control means for applying an initial torque to the electric motor.
[0007]
【The invention's effect】
Therefore, in the present invention, when the vehicle starts, the loosening control means connects the disconnection mechanism immediately before the accelerator is depressed, and controls the electric motor to apply the initial torque to the electric motor as much as the looseness of the motor drive system is reduced. Therefore, the driving feeling can be improved by reducing the discomfort to the occupant at the time of starting while ensuring the durability reliability of the motor drive system.
[0008]
In addition, even if the amount of backlash in the motor drive system changes over time, or even if the initial value of the backlash amount of the motor drive system is not managed, the play can be reduced, so the cost of the motor drive system should be reduced. Is possible.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment for realizing a drive control device for a motor four-wheel drive vehicle of the present invention will be described below with reference to the drawings.
[0010]
(First embodiment)
First, the configuration will be described.
FIG. 1 is an overall system diagram showing a drive control device for a motor four-wheel drive vehicle of a first embodiment, and FIG. 2 is a block diagram showing a 4WD control system of the first embodiment device. In the system of the first embodiment, as shown in FIG. 1, left and right front wheels 1L and 1R are driven by an engine 2 which is an internal combustion engine, and left and right rear wheels 3L and 3R can be driven by a motor 4 (electric motor) which is an electric motor. This is an example of a simple vehicle.
[0011]
As shown in FIG. 1, the output torque Te of the engine 2 is transmitted to the left and right front wheels 1L, 1R via a transmission & differential gear 5. A part of the output torque Te of the engine 2 is transmitted to the generator 7 via the endless belt 6.
[0012]
The generator 7 rotates at the rotation speed Nh obtained by multiplying the engine rotation speed Ne by the pulley ratio, and becomes a load on the engine 2 according to the field current Ifh adjusted by the 4WD controller 8, and according to the load torque. To generate electricity. The power generated by the generator 7 can be supplied to the motor 4 via the electric wire 9. A junction box 10 is provided in the middle of the electric wire 9.
[0013]
The drive torque of the motor 4 can be transmitted to the left and right rear wheels 3L and 3R via a gear reducer 11 and a clutch 12 (disconnection mechanism). Reference numeral 13 denotes a differential gear for the left and right rear wheels 3L and 3R.
[0014]
A throttle valve 15 is interposed in an intake pipe 14 (for example, an intake manifold) of the engine 2. The throttle valve 15 is an accelerator-by-wire system in which the throttle opening is adjusted and controlled according to the amount of depression of an accelerator pedal 17 and the like. That is, the throttle valve 15 uses the step motor 19 as an actuator, and the valve opening is adjusted and controlled by the rotation angle according to the number of steps of the step motor 19. The rotation angle of the step motor 19 is adjusted and controlled by an opening signal from the engine controller 18.
[0015]
The throttle sensor 16 detects a valve opening of the throttle valve 15, and the throttle sensor 16 outputs a detection signal corresponding to the detected valve opening to the engine controller 18 and the 4WD controller 8.
[0016]
An accelerator sensor 20 for detecting the amount of depression of the accelerator pedal 17 is provided. The accelerator sensor 20 outputs a detection signal corresponding to the detected amount of depression to the engine controller 18 and the 4WD controller 8.
[0017]
The engine speed sensor 21 for detecting the speed of the engine 2 outputs a detection signal corresponding to the detected depression amount to the engine controller 18 and the 4WD controller 8. .
[0018]
The engine controller 18 performs a valve opening control process based on each input signal at predetermined sampling times.
[0019]
As shown in FIG. 2, the generator 7 includes a voltage regulator 22 (regulator) for adjusting the output voltage V, and the 4WD controller 8 adjusts the field current Ifh to generate electric power for the engine 2. The load torque Th and the generated voltage V are controlled. The voltage regulator 22 receives a generator control command (field current value) from the 4WD controller 8, adjusts the field current Ifh of the generator 7 to a value corresponding to the generator control command, and And the output voltage V can be detected and output to the 4WD controller 8. The rotation speed Nh of the generator 7 can be calculated from the rotation speed Ne of the engine 2 based on the pulley ratio.
[0020]
Further, a current sensor 23 is provided in the junction box 10. The current sensor 23 detects a current value Ia of electric power supplied from the generator 7 to the motor 4, and outputs the detected armature current signal. Output to the 4WD controller 8. Further, a voltage value (voltage of the motor 4) flowing through the electric wire 9 is detected by the 4WD controller 8. In FIG. 2, reference numeral 24 denotes a relay, and interruption and connection of electric power (current) supplied to the motor 4 are controlled by a command from the 4WD controller 8.
[0021]
Further, in the motor 4, the field current Ifm is controlled by a command from the 4WD controller 8, and the drive torque Tm is adjusted by adjusting the field current Ifm. Reference numeral 25 denotes a thermistor for measuring the temperature of the motor 4.
[0022]
A motor speed sensor 26 for detecting the speed Nm of the drive shaft of the motor 4 is provided. The motor speed sensor 26 outputs the detected motor speed signal to the 4WD controller 8.
[0023]
The clutch 12 includes a hydraulic clutch, an electromagnetic clutch, and the like, and transmits torque at a torque transmission rate according to a clutch control command from the 4WD controller 8.
[0024]
Each of the wheels 1L, 1R, 3L, 3R is provided with a wheel speed sensor 27FL, 27FR, 27RL, 27RR. Each wheel speed sensor 27FL, 27FR, 27RL, 27RR outputs a pulse signal corresponding to the rotation speed of the corresponding wheel 1L, 1R, 3L, 3R to the 4WD controller 8 as a wheel speed detection value.
[0025]
The 4WD controller 8 controls the driving of the motor 4 so as to generate a driving force according to the accelerator opening from the accelerator sensor 20 (electric motor drive control means).
[0026]
The 4WD controller 8 performs control to disengage the clutch 12 when the motor 4 is not driven by the motor drive control in order to prevent the motor 4 from being rotated by the left and right rear wheels 3L and 3R and reduce friction. (Disconnection mechanism control means).
[0027]
When starting the vehicle, the 4WD controller 8 connects the clutch 12 immediately before the accelerator pedal 17 is depressed, and controls the motor 4 to apply an initial torque to the motor 4 as much as the play of the gear reducer 11 of the motor drive system is reduced ( Backlash control means).
[0028]
In the backlash control, the clutch 12 is connected when the range position detected by the inhibitor switch 28 is selected from the neutral range (N range) to the travelable range (D range). When it is detected from the switch signal from the brake switch 29 that the brake pedal is released, an initial torque is applied to the motor 4 by an amount corresponding to reducing the backlash of the gear reducer 11 or the like.
[0029]
Next, the operation will be described.
[0030]
[Gap reduction control processing]
FIG. 3 is a flowchart illustrating the flow of the play reduction control processing executed by the 4WD controller 8, and each step will be described below.
[0031]
In step S1, it is determined whether or not the range position detected by the inhibitor switch 28 is the D range. If it is the D range, the process proceeds to step S2, and if it is not the D range, the process returns to the return.
[0032]
In step S2, a connection command is output to clutch 12.
[0033]
In step S3, it is determined based on a switch signal from the brake switch 29 whether or not the brake pedal is released (brake OFF).
[0034]
In step S4, a rotation command is output to the motor 4. The command value at this time may be such that the vehicle does not start and a driving current enough to reduce the play of the gear reducer 11 is supplied to the motor 4.
[0035]
[Backlash control action]
When the gear reducer 11 is applied as the rear wheel drive system driven by the motor 4 as in the first embodiment, and a multi-plate clutch having a cam mechanism is applied as the clutch 12, the back of the gear reducer 11 is used. In addition to the lash play, the play of the amount of rotation of the cam is further added, so that the rear wheel drive system has a large play.
[0036]
Therefore, when starting, the motor 4 is stopped, the clutch 12 is released and the left and right rear wheels 3L, 3R are disconnected from the motor 4, and then the clutch 12 is engaged and the motor 4 is driven to rotate at the torque required for starting. In order to transmit the torque suddenly after the backlash due to inertia of the rear wheel drive system and the backlash is clogged, the backlash is increased, the larger the backlash is, the larger the motor torque is, Large impact torque is generated,
{Circle around (1)} The occupant is given a sense of discomfort due to the change in longitudinal acceleration when the vehicle starts.
(2) Gives an uncomfortable feeling to the occupant when starting.
{Circle around (3)} An impact force is applied to the drive system, resulting in a shortened life of the drive system.
There is a problem.
[0037]
On the other hand, in the first embodiment, when the driver selects the range position from the neutral range to the D range with the intention of starting, the process proceeds from step S1 to step S2 in the flowchart of FIG. Twelve connection commands are output. That is, in the time chart of FIG. 4, when the neutral range is selected from the neutral range at time t0, the clutch 12 shifts from the disengagement to the connection at time t1.
[0038]
Further, when the driver releases his / her foot from the brake pedal with the intention of starting, the flow proceeds to step S1, step S2, step S3, and step S4 in the flowchart of FIG. Is done. That is, in the time chart of FIG. 4, when the brake signal shifts from ON to OFF at the time t2, a motor speed command that gradually increases from the time t2 is output, and the motor 4 is thereby controlled to reduce the play amount. When the motor rotates from the time point t2 to the time point t3, the amount of play in the rear wheel drive system is reduced. At the time point t3, the play amount becomes zero.
[0039]
Thereafter, when the depression of the accelerator pedal 17 is started at time t4, the rotation speed of the motor 4 is increased by the motor rotation speed command according to the accelerator opening, the vehicle speed is also increased, and the vehicle is smoothly started in the four-wheel drive state. Is achieved.
[0040]
As described above, when the vehicle starts, the clutch 12 is connected immediately before the accelerator pedal 17 is depressed, and the play is reduced by applying the initial torque to the motor 4 as much as the play in the motor drive system is reduced. Prevents the generation of impact torque due to backlash when starting,
{Circle around (1)} A sense of discomfort due to a change in longitudinal acceleration given to the occupant at the time of starting is reduced.
{Circle around (2)} Reduce the discomfort caused by abnormal noise given to the occupant when starting.
(3) Enhance the life of the motor drive system.
The driving feeling at the time of starting is greatly improved.
[0041]
Next, effects will be described.
In the drive control device for a motor four-wheel drive vehicle of the first embodiment, the following effects can be obtained.
[0042]
(1) At the time of starting the vehicle, in the play reduction control, the clutch 12 is connected immediately before the accelerator pedal 17 is depressed, and control is performed to apply the initial torque to the motor 4 as much as the play of the motor drive system is reduced. While ensuring the durability reliability of the vehicle, it is possible to improve the running feeling by reducing the discomfort to the occupant at the time of starting. In addition, even if the amount of backlash in the motor drive system changes over time, or even if the initial value of the backlash amount of the motor drive system is not managed, the play can be reduced, so the cost of the motor drive system should be reduced. Is possible.
[0043]
(2) In the backlash control, the clutch 12 is connected when the range position is selected from the neutral range to the D range. Therefore, when the driver performs the D range selection operation with the intention of starting, the motor is reliably driven. The connection of the clutch 12 of the system can be made.
[0044]
(3) In the play reduction control, when the brake pedal is released, the initial torque is applied to the motor 4 by the amount corresponding to the play of the motor drive system, so that the driver releases the brake immediately before performing the accelerator depressing operation for starting. When the operation is performed, the motor 4 can be surely rotated to reduce backlash.
[0045]
As described above, the drive control device for a motor four-wheel drive vehicle of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and is not limited to the first embodiment. Changes and additions to the design are permitted without departing from the gist of the claimed invention.
[0046]
For example, in the first embodiment, an example has been described in which the clutch is connected based on the select operation to the D range at the time of starting and the initial torque is applied to the motor based on the brake release operation. This is because, when the driver's operation at the time of starting is considered in time series, it is common to first perform a select operation to the D range, then perform a brake release operation, and then perform an accelerator depressing operation. However, the present invention is not limited to the first embodiment as long as the clutch is connected immediately before the accelerator pedal is depressed and an initial torque is applied to the motor. For example, at the time of starting, the clutch may be engaged based on a select operation to the D range, and the initial torque may be applied to the motor after confirming the clutch engagement. Further, at the time of starting, the clutch may be connected based on the brake release operation, and the clutch connection may be confirmed to apply the initial torque to the motor.
[Brief description of the drawings]
FIG. 1 is an overall system diagram showing a drive control device of a motor four-wheel drive vehicle according to a first embodiment.
FIG. 2 is a block diagram showing a 4WD control system of the first embodiment.
FIG. 3 is a flowchart illustrating a play control process performed by a 4WD controller in the apparatus of the first embodiment.
FIG. 4 is a time chart showing characteristics of a range position, a brake signal, an accelerator opening, a clutch connection / disconnection state, a motor rotation speed command, a motor rotation speed, a play amount, and a vehicle speed during the play reduction control in the first embodiment. It is a chart.
[Explanation of symbols]
1L, 1R Left and right front wheels 2 Engines 3L, 3R Left and right rear wheels 4 Motor (electric motor)
5 Transmission & differential gear 6 Endless belt 7 Generator 8 4WD controller 9 Electric wire 10 Junction box 11 Gear reducer 12 Clutch (disconnection mechanism)
13 Differential Gear 14 Intake Pipeline 15 Throttle Valve 16 Throttle Sensor 17 Accelerator Pedal 18 Engine Controller 19 Step Motor 20 Accelerator Sensor 21 Engine Speed Sensor 22 Voltage Regulator
23 Current Sensor 24 Relay 25 Thermistor 26 Motor Speed Sensor 27FL, 27FR, 27RL, 27RR Wheel Speed Sensor 28 Inhibitor Switch 29 Brake Switch

Claims (3)

In a motor four-wheel drive vehicle in which one drive shaft is driven by an engine and the other drive shaft is driven via an electric motor driven by electric energy generated by the engine,
Electric motor drive control means for driving and controlling the electric motor to generate a driving force according to the accelerator opening,
A connection / disconnection mechanism capable of connecting / disconnecting between the electric motor and drive wheels is provided, and a connection / disconnection mechanism control unit that disconnects the connection / disconnection mechanism when the electric motor is not driven by the electric motor drive control unit,
At the start of the vehicle, the disconnection mechanism is connected immediately before the accelerator is depressed, and the loosening control means for applying an initial torque to the electric motor as much as the looseness of the motor drive system,
A drive control device for a motor four-wheel drive vehicle, comprising: The drive control device for a motor four-wheel drive vehicle according to claim 1,
The drive control device for a motor four-wheel drive vehicle, wherein the backlash control means is means for connecting the connection / disconnection mechanism when a range position is selected from a neutral range to a travelable range. A drive control device for a motor four-wheel drive vehicle according to any one of claims 1 and 2,
The drive control device for a motor four-wheel drive vehicle, wherein the backlash control unit is a unit that applies an initial torque to the motor by an amount corresponding to the backlash of the motor drive system when the brake pedal is released.

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