JP2021000927A - vehicle - Google Patents

Abstract

To provide a vehicle moving backward with a motor generator which can move backward even if the motor generator breaks down.SOLUTION: A vehicle 100 includes an engine 3, a starter generator 6, a motor generator 4 and a controller 20 for controlling an operation of the starter generator 6 and the motor generator 4. When the vehicle 100 moves backward, the controller 20 moves the vehicle 100 backward by revolving the motor generator 4 in a direction opposite to the direction for forward movement. If the motor generator 4 fails when the vehicle 100 moves backward, the controller moves the vehicle 100 backward by revolving the starter generator 6 in a direction opposite to the direction for forward movement.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hybrid vehicle including a motor generator.

Patent Document 1 discloses a vehicle including a drive motor and a forward / backward switching mechanism provided on a power transmission path between the engine and drive wheels.

JP-A-2017-65598

In the vehicle described in Patent Document 1, by rotating the motor generator in the reverse direction, it is possible to move backward without using the power of the engine, so that the forward / backward switching mechanism can be abolished.

However, when the forward / backward switching mechanism is abolished, for example, if the motor generator breaks down, the vehicle may not be able to move backward.

The present invention has been made in view of such technical problems, and an object of the present invention is to provide a vehicle that can move backward by a motor generator even if the motor generator fails.

According to an aspect of the present invention, the vehicle generates torque to start the engine or assist the driving of the engine when power is supplied from the engine and the battery, and generate rotational energy from the engine. When received, it generates a starter generator that can generate power to charge the battery, and when power is supplied from the battery, it generates torque to drive the drive wheels and inputs them from the drive wheels or the engine. If there is, the motor generator capable of generating electric power for charging the battery and the starter generator and the control device for controlling the operation of the motor generator are provided, and the control device is provided when the vehicle is moved backward. , When the motor generator is rotated in the opposite direction to the forward direction to move the vehicle backward and the vehicle is moved backward, if the motor generator is out of order, the starter generator is rotated in the opposite direction to the forward direction to the vehicle. Is characterized by moving backward.

According to the above aspect, in a vehicle moving backward by the motor generator, even if the motor generator fails, the starter generator can be rotated in the direction opposite to that in the forward direction to move backward.

FIG. 1 is a schematic configuration diagram of a vehicle according to the present embodiment. FIG. 2 is a flowchart showing control at the time of reverse movement according to the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a vehicle 100 according to an embodiment of the present invention. The vehicle 100 includes a low-voltage battery 1 as a first battery, a high-voltage battery 2 as a second battery, an engine 3 as a driving drive source, and a motor generator 4 (hereinafter, the motor generator 4 is also referred to as “MG4”). The starter motor 5 used to start the engine 3 (hereinafter, the starter motor 5 is also referred to as "SM5"), and the starter generator 6 used to generate power and assist and start the engine 3 (hereinafter referred to as "SM5"). , The starter generator 6 is also referred to as “SG6”), the DC-DC converter 7, the inverter 8, the mechanical oil pump 9 and the electric oil pump 10 as the hydraulic source, the clutch 12 as the friction fastening element, and none. It includes a speed transmission 13 (hereinafter referred to as “CVT 13”), a differential mechanism 14, a drive wheel 18, and a controller 20 as a control device for controlling various operations of the vehicle 100.

The low voltage battery 1 is a lead acid battery having a nominal voltage of DC12V. The low-voltage battery 1 is mounted on the vehicle 100 and supplies electric power to electrical components 15 (camera 15a and sensor 15b for automatic driving, navigation system 15c, audio 15d, blower 15e for air conditioner, etc.) operating at DC12V. The low voltage battery 1 is connected to the low voltage circuit 16 together with the electrical component 15. The low voltage battery 1 may be a lithium ion battery having a nominal voltage of DC12V.

The high-voltage battery 2 is a DC48V lithium-ion battery having a higher nominal voltage than the low-voltage battery 1. The nominal voltage of the high voltage battery 2 may be lower or higher than this, for example, DC30V or DC100V. The high-voltage battery 2 is connected to the high-voltage circuit 17 together with the MG4, SG6, inverter 8, electric oil pump 10, and the like.

The DC-DC converter 7 is provided on an electric circuit that connects the low-voltage battery 1 and the high-voltage battery 2. As a result, the low-voltage circuit 16 and the high-voltage circuit 17 are connected via the DC-DC converter 7. The DC-DC converter 7 converts the input voltage and outputs it. Specifically, the DC-DC converter 7 has a boosting function that boosts DC12V of the low-voltage circuit 16 to DC48V and outputs DC48V to the high-voltage circuit 17, and steps down DC48V of the high-voltage circuit 17 to DC12V to reduce the voltage. The circuit 16 has a step-down function that outputs DC12V. The DC-DC converter 7 can output a voltage of DC12V to the low voltage circuit 16 regardless of whether the engine 3 is being driven or stopped. Further, when the remaining capacity of the high-voltage battery 2 becomes low, the DC 12V of the low-voltage circuit 16 can be boosted to DC 48V and output to the high-voltage circuit 17 to charge the high-voltage battery 2.

The engine 3 is an internal combustion engine that uses gasoline, light oil, or the like as fuel, and its rotational speed, torque, or the like is controlled based on a command from the controller 20.

The clutch 12 is provided on the power transmission path between the engine 3 and the CVT 13. As the clutch 12, for example, a normally open wet multi-plate clutch is used. When the clutch 12 is engaged, the torque of the engine 3 is transmitted to the CVT 13.

The CVT 13 is arranged on the power transmission path between the clutch 12 and the differential mechanism 14, and changes the gear ratio steplessly according to the vehicle speed, the accelerator opening degree which is the operation amount of the accelerator pedal, and the like. The CVT 13 includes a primary pulley 13a, a secondary pulley 13b, and a belt 13c wound around both pulleys. In the CVT 13, the gear ratio can be changed steplessly by changing the groove widths of the primary pulley 13a and the secondary pulley 13b by flood control and changing the contact radius between the pulleys 13a and 13b and the belt 13c. The flood pressure required by the CVT 13 is generated by a hydraulic circuit (not shown) using the flood pressure generated by the mechanical oil pump 9 or the electric oil pump 10 as the original pressure.

The MG4 is a synchronous rotary electric machine in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The MG4 is connected to the shaft of the primary pulley 13a via a chain 21 wound between the sprocket provided on the shaft of the MG4 and the sprocket provided on the shaft of the primary pulley 13a. The MG 4 is controlled by applying a three-phase alternating current generated by the inverter 8 based on a command from the controller 20. The MG 4 operates as an electric motor that is rotationally driven by receiving electric power supplied from the high-voltage battery 2. Further, the MG 4 functions as a generator that generates an electromotive force at both ends of the stator coil when the rotor receives rotational energy from the engine 3 and the drive wheels 18, and can charge the high voltage battery 2.

The sprocket provided on the shaft of the MG4 and the sprocket provided on the shaft of the primary pulley 13a are configured so that the latter has a large number of teeth (for example, the number of teeth = 1: 3), and the output rotation of the MG3 is decelerated. Is transmitted to the primary pulley 13a. As a result, the torque required for the MG4 is reduced, the MG4 is miniaturized, and the degree of freedom in arranging the MG4 is improved. A gear train may be used instead of the chain 21.

The SM5 is arranged so that the pinion gear 5a can be meshed with the outer peripheral gear 3b of the flywheel 3a of the engine 3. When the engine 3 is started from a cold state for the first time (hereinafter referred to as "first start"), power is supplied from the low voltage battery 1 to the SM5, the pinion gear 5a is meshed with the outer gear 3b, the flywheel 3a, and further. The crankshaft is rotated.

The torque and output required to start the engine 3 are the largest at the first start, and are smaller at the start from the warm-up state, that is, at the restart than at the first start. This is because the temperature of the engine oil is low and the viscous resistance of the engine oil is large at the first start, whereas the temperature of the engine oil rises and the viscous resistance of the engine oil decreases after the first start. Since SG6, which will be described later, is driven via a belt, it cannot transmit a large torque. Therefore, at the first start, the SM5 is used to drive the engine 3.

The SG 6 is connected to the crankshaft of the engine 3 via the V-belt 22, and functions as a generator when receiving rotational energy from the engine 3. The electric power generated in this way is charged into the high voltage battery 2 through the inverter 8. Further, the SG 6 operates as an electric motor that is rotationally driven by receiving electric power supplied from the high-voltage battery 2, and generates torque for assisting the driving of the engine 3. Further, the SG6 is used to rotationally drive the crankshaft of the engine 3 to restart the engine 3 when the engine 3 is restarted from the idling stop state. Since the SG6 is connected to the crankshaft of the engine 3 by the V-belt 22, when the engine 3 is started, there is no gear biting noise, and a quiet and smooth start is possible. Therefore, at the time of restart, the SG6 is used to drive the engine 3.

The mechanical oil pump 9 is an oil pump that operates by transmitting the rotation of the engine 3 via the chain 23. The mechanical oil pump 9 sucks up the hydraulic oil stored in the oil pan and supplies the oil to the clutch 12 and the CVT 13 via a hydraulic circuit (not shown).

The electric oil pump 10 is an oil pump operated by electric power supplied from the high voltage battery 2. The electric oil pump 10 operates when the engine 3 is stopped and the mechanical oil pump 9 cannot be driven by the engine 3, such as in an idle stop state, and sucks up the hydraulic oil stored in the oil pan like the mechanical oil pump 9. , Oil is supplied to the clutch 12 and the CVT 13 via a hydraulic circuit (not shown). In particular, by securing the necessary flood pressure in the CVT 13, the slip of the belt 13c is suppressed. The electric oil pump 10 may be an oil pump operated by electric power supplied from the low voltage battery 1.

The controller 20 is composed of one or a plurality of microcomputers including a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 20 operates the engine 3, the inverter 8 (SG6, the electric oil pump 10), the DC-DC converter 7, the SM5, the clutch 12, the CVT 13, and the like by executing the program stored in the ROM or the RAM by the CPU. Control in an integrated manner.

As the operation mode of the vehicle 100, the controller 20 drives the MG4 with the electric power supplied from the high-voltage battery 2 and travels by the driving force of the MG4 only, and the engine traveling mode of traveling by the driving force of the engine 3 only. And the HEV mode in which the vehicle travels according to the driving force of the engine 3 and the driving force of the MG 4.

In the EV mode, the vehicle 100 travels by driving only the MG 4 with the electric power from the high voltage battery 2 in a state where the clutch 12 is released. The EV mode is selected when the required output of the vehicle 100 is low and the remaining capacity of the high voltage battery 2 is sufficient.

In the engine running mode, the vehicle 100 runs by driving only the engine 3 with the clutch 12 engaged. The engine running mode is selected when the required output of the vehicle 100 is relatively high.

In the HEV mode, the vehicle 100 runs by driving the engine 3 and the MG 4 with the clutch 12 engaged. The HEV mode is selected when the required output of the vehicle 100 is high, specifically, when the required output of the vehicle 100 cannot be supplemented only by the output of the engine 3.

The controller 20 selects a driving mode based on the accelerator opening, the pedal effort of the brake pedal, and the vehicle speed in consideration of a driving mode selection map (not shown), and sets the engines 3 and MG 4 so that the selected driving mode is realized. Drive.

Vehicle 100 does not include a torque converter. Therefore, in the WSC region when moving forward (a low vehicle speed region where the vehicle speed is a predetermined vehicle speed (for example, 10 km / h) or less, which is used when starting / decelerating / stopping), the controller 20 transmits torque while slipping the clutch 12. In other words, WSC (Wet Start Clutch) control for engaging the clutch 12 while slipping is executed.

Specifically, when the shift range of the CVT 13 is switched to the forward range (D range, etc.) and the vehicle 100 starts, the controller 20 gradually increases the hydraulic pressure supplied to the clutch 12 and slips the clutch 12. Gradually tighten while letting. Then, when the vehicle speed reaches the predetermined vehicle speed, the controller 20 completely engages the clutch 12 and ends the WSC control. By controlling the clutch 12 in this way, it is possible to suppress the occurrence of a shock at the time of starting and to suppress the engine stall.

Further, the vehicle 100 does not have a forward / backward switching mechanism. Therefore, since the vehicle 100 cannot move backward by the power of the engine 3, it moves backward by the power of MG4. Specifically, when the shift range of the CVT 13 is switched to the reverse range (R range), the controller 20 rotates the MG 4 in the direction opposite to that when moving forward so that the vehicle speed becomes the vehicle speed according to the accelerator opening. Controls MG4. When moving backward, the clutch 12 is released except when the power of SG6 described later is used. When the clutch 12 is engaged, when the engine 3 is operating, the engine 3 outputs torque in the forward direction, so that the torque of the engine 3 is transmitted to the CVT 13 and the drive wheels 18. , There is a risk that the reverse operation will be hindered or the engine 3 will stop unintentionally. Further, even when the engine 3 is stopped, the torque of the MG 4 is transmitted to the engine 3 side via the clutch 12. In this case, a part of the torque of the MG 4 is used to rotate the engine 3, so that the torque of the MG 4 is wasted. Therefore, when moving backward, the clutch 12 is released except when the power of SG6 described later is used.

By the way, in the case of moving backward by MG4, if MG4 is out of order, it cannot be moved backward. Therefore, in the present embodiment, when the vehicle 100 is moved backward, if the MG4 is out of order, the SG6 is rotated in the direction opposite to that when the vehicle 100 is moved forward to move the vehicle 100 backward.

Hereinafter, the control at the time of reverse movement in the vehicle 100 of the present embodiment will be specifically described with reference to the flowchart shown in FIG.

When it is detected in step S1 that the reverse movement has started, the controller 20 determines in step S2 whether or not MG4 has failed. When, for example, the controller 20 detects a state in which the MG4 cannot be energized, or a state in which the rotation speed and temperature of the MG4 show abnormal values, the controller 20 determines that the MG4 is out of order. If the MG4 is not out of order, the process proceeds to step S3, and if the MG4 is out of order, the process proceeds to step S10.

In step S3, it is determined whether or not the load is high. Specifically, the controller 20 determines, for example, whether the vehicle 100 is in a backward climbing state or a towing state (a state in which another vehicle is towing). The controller 20 determines whether or not the vehicle 100 is in a climbing state or a towing state based on the road gradient detected by the gradient sensor (not shown), the output torque, the vehicle speed, and the like. In step S3, it is determined whether or not the torque by MG4 satisfies the required torque (for moving the vehicle 100 backward). If it is determined that the vehicle 100 is not in the high load state, the process proceeds to step S4, and if it is determined that the vehicle 100 is in the high load state, the process proceeds to step S5.

In step S4, only MG4 is driven. The controller 20 releases the clutch 12 and rotates the MG 4 in the direction opposite to that when moving forward. As a result, the vehicle 100 starts moving backward. After that, the controller 20 controls MG4 so that the vehicle speed becomes the vehicle speed according to the accelerator opening degree.

Next, a case where it is determined in step S3 that the vehicle 100 is in a high load state and the process proceeds to step S5 will be described. In step S5, the controller 20 rotates the MG 4 in the direction opposite to that at the time of forward movement, and stops the engine 3 when the engine 3 is driven. Further, the controller 20 rotates the SG 6 in the direction opposite to that in the forward direction. That is, when the vehicle 100 is in a high load state, the torque of the SG6 assists the vehicle 100 in moving backward. At the start of reverse movement, the clutch 12 is released because the vehicle 100 is stopped.

Then, the controller 20 executes WSC control on the clutch 12. As a result, the torque of the SG6 is gradually transmitted to the drive wheels 18, and the assist torque of the SG6 gradually increases.

In step S6, it is determined whether or not the vehicle speed V is larger than the threshold value V0. If the vehicle speed V is larger than the threshold value V0, the process proceeds to step S7, and if the vehicle speed V is equal to or less than the threshold value V0, the process proceeds to step S8.

In step S7, the clutch 12 is completely engaged. By completely engaging the clutch 12 after executing WSC control in this way, the occurrence of shock can be suppressed.

In step S8, it is determined whether or not the predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step S6. On the other hand, if the predetermined time has elapsed, the process proceeds to step S9.

In step S9, a warning is generated. The warning method is, for example, displaying a warning on a display device in the vehicle, turning on a warning light, or alerting the driver with a voice or a warning sound. As a result, the driver can recognize that an abnormality has occurred and take appropriate measures such as stopping the vehicle 100. In step S9, the vehicle 100 may be stopped by the automatic brake at the same time as the warning is generated.

As described above, in the present embodiment, when the vehicle 100 is in a high load state, a warning is issued when the vehicle speed V does not reach V0 within a predetermined time even if the MG4 and SG6 are driven. In such a situation, one of MG4 and SG6 is abnormal, or the driving force of MG4 and SG6 is not enough to move backward. Therefore, the driver can be alerted by issuing a warning. ..

Next, in step S2, a case where it is determined that MG4 is out of order (flow in step S10 or less) will be described.

In step S10, only SG6 is rotated in the direction opposite to that at the time of forward movement, and when the engine 3 is driven, the engine 3 is stopped. Further, the controller 20 rotates the SG 6 in the direction opposite to that in the forward direction. At the start of reverse movement, the clutch 12 is released because the vehicle 100 is stopped.

Then, the controller 20 executes WSC control on the clutch 12. As a result, the torque of the SG6 is gradually transmitted to the drive wheels 18, and the assist torque of the SG6 gradually increases.

Since steps S11 to S14 are the same as steps S6 to S9, description thereof will be omitted.

As described above, in the present embodiment, when the MG4 fails, the vehicle 100 can be moved backward by driving the SG6. Further, even when the vehicle is moving backward only with SG6, a warning is issued when the vehicle speed V does not reach V0 within a predetermined time. In such a situation, the SG6 has an abnormality, or the driving force of the SG6 alone is not enough to move backward. Therefore, the driver can be alerted by issuing a warning.

The effects of the above-described embodiments configured as described above will be collectively described.

The vehicle 100 of the present embodiment has a torque for starting the engine 3 or assisting the driving of the engine 3 when power is supplied from the engine 3 and the battery (low voltage battery 1 or high voltage battery 2). A starter generator 6 capable of generating power for charging the battery (low voltage battery 1 or high voltage battery 2) and a battery (low voltage battery 1 or high voltage battery 2) when the engine 3 receives rotational energy. When power is supplied from the high-voltage battery 2), torque for driving the drive wheels 18 is generated, and when there is an input from the drive wheels 18 or the engine 3, the battery (low-voltage battery 1 or It includes a motor generator 4 capable of generating electric power for charging the high-voltage battery 2), and a control device (controller 20) for controlling the operation of the starter generator 6 and the motor generator 4.

When the control device (controller 20) moves the vehicle 100 backward, the motor generator 4 is rotated in the direction opposite to that at the time of forward movement to move the vehicle 100 backward, and when the vehicle 100 is moved backward, the motor generator 4 fails. If so, the starter generator 6 is rotated in the direction opposite to that in the forward direction to move the vehicle 100 backward.

According to this configuration, since the vehicle 100 can be moved backward by the motor generator 4, the forward / backward switching mechanism can be abolished. Further, even if the motor generator 4 breaks down, the vehicle 100 can be moved backward by rotating the starter generator 6 in the direction opposite to that when moving forward. Therefore, the fail-safe function of the vehicle 100 can be improved (effects corresponding to claims 1 and 5).

In the vehicle 100, the control device (controller 20) assists by the torque of the starter generator 6 when the vehicle 100 is in a high load state when the vehicle 100 is moved backward.

When the vehicle 100 is moved backward, if the vehicle 100 is in a high load state, it can be assisted by the torque of the starter generator 6, so that it is possible to suppress an increase in the size of the motor generator 4 (effect corresponding to claim 2).

The vehicle 100 further includes a continuously variable transmission 13 and a friction engaging element (clutch 12) provided between the engine 3 and the continuously variable transmission 13, and the control device (controller 20) moves the vehicle 100 backward. When assisting by the starter generator 6 at the time of making the clutch engage, the friction engaging element (clutch 12) is engaged while slipping.

By engaging the friction engaging element (clutch 12) while slipping, that is, by executing WSC control on the friction engaging element (clutch 12), a shock is generated when the friction engaging element (clutch 12) is engaged. This can be suppressed (effect corresponding to claim 3).

The control device (controller 20) issues a warning when the vehicle speed V does not reach a predetermined value (threshold value V0) within a predetermined time when the vehicle 100 is moved backward and is assisted by the starter generator 6. ..

Since there is an abnormality in either MG4 or SG6, or the driving force of MG4 or SG6 is not enough to move backward, the driver can be alerted by issuing a warning (corresponding to claim 4). Effect).

Although the embodiment of the present invention has been described above, the above-described embodiment is only one of the application examples of the present invention, and the purpose of limiting the technical scope of the present invention to the specific configuration of the above-described embodiment is defined. is not.

The position where the MG 4 is provided is not limited to the position shown in FIG. 1, and may be any position as long as it is on the downstream side of the clutch 12 in the power transmission path.

Further, although the threshold values in step S6 and step S11 in FIG. 2 are set to the same threshold value V0, these threshold values may be different values.

In the embodiment shown in FIG. 1, the clutch 12 is provided on the downstream side of the mechanical oil pump 9 in the power transmission path from the engine 3 to the continuously variable transmission 13, but is provided at a position adjacent to the engine 3. You may do so. Since the torque converter is not provided in the present embodiment, the size of the device can be suppressed by providing the clutch 12 at a position where the torque converter is attached. Further, by providing the clutch 12 at a position adjacent to the engine 3, a space in the radial direction of the clutch 12 can be secured, so that the number of stacked plates of the clutch 12 can be reduced.

1: Low voltage battery 2: High voltage battery 3: Engine 4: Motor generator 5: Starter motor 6: Starter generator 12: Clutch (friction fastening mechanism)
13: Continuously variable transmission 20: Controller (control device)
100: Vehicle

Claims (5)

With the engine
When power is supplied from the battery, torque is generated to start the engine or assist the driving of the engine, and when rotational energy is received from the engine, the battery is charged. With a starter generator that can generate electricity,
When power is supplied from the battery, torque for driving the drive wheels can be generated, and when there is an input from the drive wheels or the engine, power for charging the battery can be generated. Motor generator and
In a vehicle provided with the starter generator and a control device for controlling the operation of the motor generator.
The control device is
When the vehicle is to be moved backward, the motor generator is rotated in the direction opposite to that when the vehicle is moved forward to move the vehicle backward.
If the motor generator is out of order when the vehicle is moved backward, the starter generator is rotated in the direction opposite to that when the vehicle is moved forward to move the vehicle backward.
A vehicle characterized by that. The vehicle according to claim 1.
When the vehicle is moved backward, the control device assists by the torque of the starter generator when the vehicle is in a high load state.
A vehicle characterized by that. The vehicle according to claim 2.
With a continuously variable transmission
Further comprising a friction fastening element provided between the engine and the continuously variable transmission.
When the control device is assisted by the starter generator when the vehicle is moved backward, the friction fastening element is fastened while slipping.
A vehicle characterized by that. The vehicle according to claim 2 or 3.
The control device issues a warning when the vehicle speed does not reach a predetermined value within a predetermined time when assisted by the starter generator when the vehicle is moved backward.
A vehicle characterized by that. With the engine
When power is supplied from the battery, torque is generated to start the engine or assist the driving of the engine, and when rotational energy is received from the engine, the battery is charged. With a starter generator that can generate electricity,
When power is supplied from the battery, torque for driving the drive wheels can be generated, and when there is an input from the drive wheels or the engine, power for charging the battery can be generated. Motor generator and
In a vehicle control method for controlling a vehicle including the starter generator and a control device for controlling the operation of the motor generator.
When the vehicle is to be moved backward, the motor generator is rotated in the direction opposite to that when the vehicle is moved forward to move the vehicle backward.
If the motor generator is out of order when the vehicle is moved backward, the starter generator is rotated in the direction opposite to that when the vehicle is moved forward to move the vehicle backward.
A vehicle control method characterized by that.

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