JP5240004B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device, and more particularly to a control device for a vehicle including a first wheel driven by an engine and a second wheel driven by a motor, particularly a four-wheel drive vehicle.

  Patent Document 1 discloses a four-wheel drive vehicle having an engine-driven front wheel and a generator, a left rear wheel driven by a left induction motor, and a right rear wheel driven by a right dielectric motor. The generator to be driven is electrically connected to the left and right induction motors respectively driven by the motor, and when a difference in rotational speed occurs between the left and right rear wheels, the difference between the rotational speeds of the left and right induction motors is eliminated. A control device has been proposed in which either one automatically generates a drive torque.

  In Patent Document 2, in a four-wheel drive vehicle having a front wheel and an AC generator driven by an engine and a rear wheel driven by an induction motor, the AC generator and the induction motor are electrically connected, There has been proposed a control device in which a driving torque is generated in an induction motor by an AC voltage output from an AC generator, and a rear wheel is driven by the driving torque. In Patent Document 2, an induction motor that normally drives the rear wheel is used as a generator at high speeds or downhills, and facilities for charging or consuming electricity generated by the induction motor are provided in the vehicle. Thus, it is disclosed that a braking force such as regenerative braking and power generation braking can be obtained.

JP 2002-218604 A (Claim 1, paragraph 0036) Japanese Patent Laying-Open No. 2005-312273 (paragraphs 0023 and 0030)

  However, according to the braking method disclosed in Patent Document 1, it is necessary to add new equipment such as a battery, an inverter, and a resistor in order to apply a braking torque obtained electrically to a wheel driven by a motor. There is a problem that.

  Patent Document 2 does not specifically disclose control for applying braking torque obtained electrically to a wheel driven by a motor.

  An object of the present invention is to provide a vehicle control device that can apply an electric braking torque to a wheel driven by a motor by using a simple configuration or by utilizing an existing configuration.

  In a first aspect, the present invention provides a vehicle in which a first wheel can be driven by an engine and a second wheel can be directly or indirectly connected to a rotor of an induction motor and driven by a motor. A generator that includes a rotor that is driven by being directly or indirectly connected to the engine and that is freely energized with a field current and that can output an AC voltage having a frequency corresponding to the engine speed; and the induction motor A wiring for electrically connecting the generator and the induction motor, a rotational speed of the engine, a rotational speed of the rotor of the generator, or an AC voltage so that a rotating magnetic field by the AC voltage can be freely generated. And a second signal corresponding to the rotation speed of the second wheel or the rotation speed of the rotor of the induction motor, and the first and second signals. Based on signal A control unit that controls at least on / off of a field current that is passed through the generator, and the control unit rotates the rotor of the generator based on the first and second signals. When it is determined that the number is lower than the number of rotations of the rotor of the induction motor, the field current is supplied to the generator, and the frequency of the induction motor is lower than the rotation frequency of the rotor. By outputting an alternating voltage and causing the induction motor to generate the rotating magnetic field due to the alternating voltage, the induction motor is operated in a region where the slip is negative, and through the rotor of the induction motor, the Provided is a vehicle control device in which a braking torque can be applied to a second wheel.

(1) When the engine speed decreases or decreases, such as during braking, the rotation speed of the induction motor, in which the rotation speed of the generator rotor rotated by the engine is rotated by the wheel driven by the motor A state occurs in which the rotational speed is lower than the rotational speed of the child. At this time, when the control unit supplies a field current to the generator, the frequency of the AC voltage output from the generator becomes lower than the rotation frequency of the rotor of the induction motor. Thus, when an alternating voltage having a relatively low frequency is applied to the induction motor, the rotational speed of the rotating magnetic field of the induction motor becomes lower than the rotational speed of the rotor of the induction motor, that is, the induction motor is Driving is performed in a region where the slip is negative, and braking torque is applied to the rotor of the induction motor. Thus, the control unit can apply an electrical braking torque to the wheels driven by the motor via the rotor of the induction motor as necessary during braking or the like.
(2) According to the present invention, an electric braking torque is motor-driven as required by a simple configuration, that is, a configuration in which an engine-driven generator is connected to an induction motor that drives a predetermined wheel. Applied to the wheel.
(3) According to the present invention, even when expensive equipment such as an inverter and a battery is not newly installed in the vehicle, for example, it is necessary at the time of braking using a configuration for driving a predetermined wheel by a motor. Accordingly, an electrical braking torque can be applied to the motor driven wheel.
(4) According to the present invention, since an electric braking force can be applied to the motor driven wheel, the hydraulic brake provided for the motor driven wheel can be downsized or reduced in capacity. Is possible. It should be noted that the hydraulic brake can be abolished in a small vehicle having a small load applied to a wheel driven by a motor, for example, a rear wheel, during braking. By reducing or eliminating the hydraulic brake as described above, an increase in weight due to the provision of the induction motor is offset, and an increase in the unsprung weight of the vehicle is also suppressed. Thereby, the fall of riding comfort and exercise | movement performance resulting from attaching the induction motor which drives a vehicle is suppressed.

1 is a block diagram of a vehicle control device according to an embodiment of the present invention. It is a block diagram explaining the principal part of the control apparatus shown in FIG. It is a figure which shows the torque-slip characteristic of the induction motor shown in FIG.1 and FIG.2. It is a flowchart explaining the operation | movement at the time of the control apparatus shown in FIG.1 and FIG.2 applying a braking torque to a rear wheel. It is a timing chart explaining the operation | movement at the time of the control apparatus shown in FIG.1 and FIG.2 applying a braking torque to a rear wheel.

  The vehicle control device according to an embodiment of the present invention includes a brake switch that outputs a third signal indicating a braking intention of a user of the vehicle, and the control unit is based on the third signal, During braking, a field current is applied to the generator, and braking torque is applied to the second wheel by the induction motor. According to this aspect, an electric braking force can be obtained from the induction motor in synchronization with the user's intention.

  In the vehicle control device according to the embodiment of the present invention, when the control unit determines that the rotation speed of the rotor of the generator is higher than the rotation speed of the rotor of the induction motor, the power generation By causing the machine to pass the field current, outputting the AC voltage having a frequency higher than the rotational frequency of the rotor of the induction motor, and causing the induction motor to generate the rotating magnetic field by the AC voltage. The induction motor is operated in a region where the slip is positive, and a driving torque can be applied to the second wheel via the rotor of the induction motor. According to this embodiment, an electric braking force can be obtained from the induction motor by using the drive induction motor as necessary.

  In the vehicle control apparatus according to the embodiment of the present invention, a relay that switches a rotation direction of the rotating magnetic field of the induction motor is connected in the middle of the connection, and the control unit moves forward and backward by switching the relay. In both cases, a braking torque can be applied to the second wheel. According to this aspect, an electric braking force can be obtained regardless of the traveling direction of the vehicle.

  In the vehicle control device according to the embodiment of the present invention, the control unit variably sets the brake feeling through the braking torque applied to the second wheel by controlling the waveform of the field current. To do. According to this embodiment, the brake feeling can be improved by the electric braking torque.

  In the vehicle control apparatus according to the embodiment of the present invention, the control unit responds to a speed ratio (gear ratio, etc.) of a transmission connected between the engine and the first wheel according to the engine speed. To control the field current.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a vehicle control apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a main part of the control device shown in FIG.

[Four-wheel drive vehicle]
Referring to FIGS. 1 and 2, a four-wheel drive vehicle 31 includes left and right front wheels (first wheels) 1, 1 that can be driven by an engine 3, and rotors 4 a, 4 a of left and right induction motors 4, 4. Left and right rear wheels (second wheels) 2 and 2 connected to each other. The power of the engine 3 is shifted through the transmission 8 and further transmitted to the left and right front wheels 1 and 1 through the differential mechanism 9. An alternating current is distributed to the left and right induction motors 4 and 4 via a distribution relay 4r. In the present embodiment, the left and right front wheels 1 and 1, the left and right rear wheels 2 and 2, and the left and right induction motors 4 and 4 can be handled in an equivalent manner. The wheel 2 and the induction motor 4 will be described.

[Control device for four-wheel drive vehicle]
The control device 32 of the four-wheel drive vehicle 31 includes a rotor 5a driven by the engine 3, and is freely energized with a field current 24, and can freely output an AC voltage 25 having a frequency corresponding to the engine speed. 5 The power of the engine 3 is transmitted to the rotor 5 a of the generator 5 through the pulley set 10. The power of the engine 3 is also transmitted to the auxiliary generator 11. The auxiliary generator 11 can charge the battery 14. The electric power of the battery 14 is supplied to the control unit 7 described later. The induction motor 4 is a three-phase AC induction motor, the generator 5 is a three-phase AC synchronous generator, and both have a symmetrical configuration.

  The control device 32 has a connection 6 that electrically connects the generator 5 and the induction motor 4 so that a rotating magnetic field by the AC voltage 25 can be freely generated in the induction motor 4. In the middle of the connection 6, a phase switching relay 6 r that switches the rotation direction of the rotating magnetic field of the induction motor 4 is connected.

  The control device 32 includes an engine speed signal (first signal) 21 corresponding to the rotational speed of the engine 3, the rotational speed of the rotor 5 a of the generator 5 or the frequency of the AC voltage 25, and the rotational speed of the rear wheel 4. The rear wheel speed signal (second signal) 22 corresponding to the speed of the rotor 4a of the induction motor 4 is input, and based on the engine speed signal and the rear wheel speed signals 21 and 22, the field And a control unit 7 that controls at least on / off of the current 24. The control unit 7 can be composed of a computer or ECU that executes a predetermined program.

[Various sensors]
The engine 3 is provided with an engine speed sensor 3s that detects the engine speed and outputs an engine speed signal (first signal) 21. The control unit 7 can calculate the rotation speed of the rotor 5 a of the generator 5, that is, the frequency of the AC voltage 25 output from the generator 5 from the engine rotation speed and the gear ratio of the pulley set 10.

  The rear wheel 2 is provided with a rear wheel speed sensor 2 s that detects the rear wheel speed and outputs a rear wheel speed signal (second signal) 22. A reduction gear 12 is connected between the rotor 4 a of the induction motor 4 and the rear wheel 2. Therefore, the control unit 7 can calculate the rotation speed of the rotor 4 a of the induction motor 4 from the rear wheel rotation speed and the reduction gear ratio of the speed reducer 12.

  The brake pedal 13 operated by the user is provided with a brake switch 13s that outputs a brake signal (third signal) indicating the user's intention to brake.

  In addition, a temperature sensor that detects the temperature of the induction motor 4, a shift position sensor, a side brake switch that detects the operation state of the side brake, and the like are installed at predetermined positions of the four-wheel drive vehicle 31. The controller 7 can execute various controls based on detection signals output from these sensors and switches.

[Control unit]
In particular, referring to FIG. 2, the control unit 7 rotates the rotor 5 a of the generator 5 based on the engine speed signal (first signal) 21 and the rear wheel speed signal (second signal) 22. When it is determined that the number is lower than the rotational speed of the rotor 4 a of the induction motor 4, the generator 5 is energized (turned on) with the field current 24 by the power supplied from the battery 14 to rotate the induction motor 4. By causing the induction motor 4 to generate a rotating magnetic field generated by the AC voltage 25 by outputting an alternating voltage 25 having a frequency lower than the rotational frequency of the child 4a, the induction motor 4 can generate a “slip” as shown in FIG. Is operated in a negative region ", and braking torque can be applied to the rear wheel 2 via the rotor 4a.

  In particular, the controller 7 applies the field current 24 to the generator 5 based on the brake signal (third signal) 23 during braking, and the induction motor 4 applies the rear wheel 2 to the rear wheel 2 as described above. Apply braking torque. The control unit 7 can apply braking torque to the rear wheels 2 in both forward and reverse travel of the four-wheel drive vehicle 31 by switching the phase switching relay 6r.

[Use induction motor 4 in areas where the slip is negative]
FIG. 3 is a diagram showing torque-slip characteristics of the induction motor shown in FIGS. 1 and 2. Referring to FIGS. 1 to 3, the induction motor 4 according to the present embodiment applies braking torque to the rear wheel 2 during braking, which is used in a “slip-negative region” indicated by hatching in FIG. 3. be able to.

  The reason is that during braking, the engine speed decreases or becomes idling speed, so the rotational speed of the rotor 5a of the generator 5 is the rotation of the rotor 4a of the induction motor 4 driven by the rear wheel 2. The generator 5 outputs an AC voltage 25 having a frequency lower than the rotational frequency of the rotor 4a of the induction motor 4, and generates a relative frequency relative to the frequency. This is because the braking torque is applied to the rotor 4 a of the induction motor 4 by inputting a low AC voltage 25 to the primary side of the induction motor 4.

  When the engine speed is sufficiently high, that is, when the controller 7 determines that the rotational speed of the rotor 5a of the generator 5 is higher than the rotational speed of the rotor 4a of the induction motor 4, the generator 5 is supplied with a field current 24 to output an AC voltage 25 having a frequency higher than the rotation frequency of the rotor 4 of the induction motor 4, and the induction motor 4 is caused to generate a rotating magnetic field by the AC voltage 25. The induction motor 4 is operated in a “region where the slip is positive (0 <s <1)”, and a driving torque can be applied to the rear wheel 1 via the rotor 4 a of the induction motor 4.

  FIG. 4 is a flowchart for explaining the operation when the control device shown in FIGS. 1 and 2 applies braking torque to the rear wheels. FIG. 5 is a timing chart for explaining the operation when the control device shown in FIGS. 1 and 2 applies braking torque to the rear wheels.

  Referring to FIGS. 2, 4, and 5, in step S <b> 1, the control unit 7 determines the presence or absence of a brake operation by the user based on the brake signal 23, and the brake pedal 13 is operated and the brake is on. In step S2, the routine is terminated when the brake pedal 13 is not operated and the brake is off.

  When the brake 13 is turned on, the engine speed (generator rotor rotation frequency) is reduced as the transmission 8 shown in FIG. 1 is slowed down (gear down), or the engine 3 is turned off or its output is reduced. 27) is lowered prior to the rear wheel speed (22), and the speed (27) of the rotor 5a of the generator 5 driven by the engine is also rotated by the rear wheel 2. Prior to the rotational speed of the rotor 4a of the induction motor 4 (see the induction motor rotor rotational frequency 26), the speed decreases.

  In step S <b> 2, the control unit 7 compares and determines the magnitude of the rotational speed (27) of the rotor 5 a of the generator 5 and the rotational speed (26) of the rotor 4 a of the induction motor 4. When the rotational speed (27) of the child 5a is lower than the rotational speed (26) of the rotor 4a of the induction motor 4, that is, M: “induction motor rotor rotational frequency” (26)> ALT: “generator rotor In the case of “rotational frequency” (27), the process proceeds to step S3. Otherwise, this routine is terminated.

  In step S <b> 3, the control unit 7 energizes the generator 5 with a field current 24 based on electric power supplied from the battery 14 to generate a three-phase AC voltage 25. The frequency of the AC voltage 25 is lower than the rotation frequency of the rotor 4 a of the induction motor 4. As a result, the induction motor 4 is operated in the “slip-negative region” indicated by hatching in FIG. 3, and the braking torque is applied to the rotor 4a, and the rear wheels connected to the rotor 4a. 2, an electric braking force is applied, and the rear wheel rotational speed (22) gradually decreases. The brake feeling can be freely controlled by changing the magnitude of the AC voltage 25 and the like by controlling the waveform of the field current 24.

  In step S4, the control unit 7 compares the rotational speed (27) of the rotor 5a of the generator 5 with the rotational speed (26) of the rotor 4a of the induction motor 4, and determines the rear wheel rotational speed ( If 22) is sufficiently reduced, that is, if M: “induction motor rotor rotation frequency” (26) <ALT: “generator rotor rotation frequency” (27), the process proceeds to step S5, and the field The energization of the current 24 is stopped and this routine is terminated. If not, the process returns to step S3 and the energization of the field current 24 is continued.

  The present invention is suitably applied to a four-wheel drive vehicle driven by an engine and a drive motor, particularly a part-time four-wheel drive vehicle.

1 Front wheel (first wheel)
2 Rear wheel (second wheel)
2s Rear wheel rotational speed sensor 3 Engine 3s Engine rotational speed sensor 4 Induction motor 4a Rotor 4r Distribution relay 5 Generator 5a Rotor 6 Connection 6r Phase switching relay 7 Control unit 8 Transmission 9 Differential mechanism 10 Pulley set 11 Power generation for auxiliary machine Machine 12 Reducer 13 Brake pedal 13s Brake switch 14 Battery 21 Engine speed signal (engine speed, first signal)
22 Rear wheel speed signal (rear wheel speed, second signal)
23 Brake signal (third signal)
24 Field current 25 AC voltage 26 Induction motor rotor rotation frequency (rotation speed of induction motor rotor)
27 Rotation frequency of generator rotor (rotation frequency of generator rotor)
31 Four-wheel Drive Vehicle 32 Control Device

Claims (5)

In a vehicle in which the first wheel can be driven by the engine and the second wheel can be directly or indirectly connected to the rotor of the induction motor and can be driven by a motor.
A generator that includes a rotor that is driven by being directly or indirectly connected to the engine and that is freely energized with a field current, and that can output an AC voltage having a frequency according to the engine speed;
A connection for electrically connecting the generator and the induction motor so that a rotating magnetic field by the AC voltage can be freely generated in the induction motor;
A first signal corresponding to a rotational speed of the engine, a rotational speed of the rotor of the generator or a frequency of the AC voltage, a rotational speed of the second wheel, or a rotational speed of the rotor of the induction motor; And a control unit that controls at least on / off of a field current supplied to the generator based on the first and second signals.
The controller is
When it is determined that the rotational speed of the rotor of the generator is lower than the rotational speed of the rotor of the induction motor based on the first and second signals,
The field current is supplied to the generator to output the AC voltage having a frequency lower than the rotation frequency of the rotor of the induction motor, and the induction motor is caused to generate the rotating magnetic field by the AC voltage. By
The induction motor is operated in a region where the slip is negative, and braking torque can be applied to the second wheel via the rotor of the induction motor.
The vehicle control apparatus characterized by the above-mentioned. A brake switch that outputs a third signal indicating the brake intention of the user of the vehicle;
The control unit causes the generator current to flow through the generator based on the third signal and applies the braking torque to the second wheel by the induction motor based on the third signal. The vehicle control device according to claim 1. The controller is
When it is determined that the rotational speed of the rotor of the generator is higher than the rotational speed of the rotor of the induction motor,
The field current is supplied to the generator to output the AC voltage having a frequency higher than the rotation frequency of the rotor of the induction motor, and the induction motor is caused to generate the rotating magnetic field by the AC voltage. By
The induction motor is operated in a region where the slip is positive, and drive torque can be applied to the second wheel via the rotor of the induction motor.
The vehicle control apparatus according to claim 1 or 2, wherein In the middle of the connection, a relay that switches the rotation direction of the rotating magnetic field of the induction motor is connected,
4. The vehicle control according to claim 1, wherein the control unit is capable of applying a braking torque to the second wheel both forward and backward by switching the relay. 5. apparatus.   The control unit variably sets a brake feeling through the braking torque applied to the second wheel by controlling the waveform of the field current. The vehicle control device according to any one of the above.

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