JP2010111190A - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly control the number of revolutions of a motor generator by controlling an engagement mechanism connected to the motor generator. <P>SOLUTION: A control device of a hybrid vehicle is applied to the hybrid vehicle equipped with an engine, the motor generator, and the engagement mechanism capable of changing the number of revolutions of the motor generator by the change of engagement torque. Concretely, when it is not possible to control the number of revolutions of the motor generator by direct control of the motor generator, the control means controls the engagement mechanism to control the number of revolutions of the motor generator. That is, the control means indirectly controls the number of revolutions of the motor generator by adjusting the engagement torque in the engagement mechanism. Thus, even when the input of a battery is restricted, or when the abnormality of the motor generator is detected, it is possible to properly control the number of revolutions of the motor generator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device suitable for a hybrid vehicle.

  Hybrid vehicles that include a power source such as a generator (first motor generator) and an electric motor (second motor generator) in addition to the engine are known. In a hybrid vehicle, the engine is operated in a highly efficient state as much as possible, while excess or deficiency of driving force or engine braking force is compensated by the first motor generator or the second motor generator.

  For example, Patent Document 1 proposes a hybrid vehicle configured to be able to switch between a continuously variable transmission mode (continuously variable transmission state) and a fixed transmission mode (continuous transmission state). In this hybrid vehicle, an engine, a first motor generator, and a drive shaft are coupled to each rotating element of the planetary gear mechanism, a brake is connected to the rotor of the first motor generator, and a second is connected to the drive shaft. The motor generator is connected. In a state where the brake is released, a reaction torque corresponding to the engine torque is output to the first motor generator, and the rotation speed of the first motor generator is continuously changed. As a result, the rotational speed of the engine continuously changes, and the operation in the continuously variable transmission mode is executed. On the other hand, when the brake is engaged, the rotation of the first motor generator is fixed, and the rotation of one rotating element in the planetary gear mechanism is prevented. As a result, the transmission ratio is fixed, and the operation in the fixed transmission mode is executed.

JP-A-2005-278387

  However, in the technique described in Patent Document 1 described above, when the battery input restriction or the abnormality of the first motor generator occurs, the rotational speed of the first motor generator is not limited to the continuously variable transmission mode. In some cases, the control could not be performed properly.

  The present invention has been made to solve the above-described problems, and is a hybrid capable of appropriately controlling the rotational speed of a motor generator by controlling an engagement mechanism connected to the motor generator. An object of the present invention is to provide a vehicle control device.

  In one aspect of the present invention, a hybrid vehicle applied to a hybrid vehicle including an engine, a motor generator, and an engagement mechanism capable of changing the rotation speed of the rotation shaft of the motor generator by changing the engagement torque. When the rotational speed of the rotation shaft of the motor generator cannot be controlled by direct control on the motor generator, the control device performs control on the engagement mechanism to control the rotation shaft of the motor generator. Control means for controlling the rotational speed is provided.

  The above hybrid vehicle control device is preferably applied to a hybrid vehicle including an engine, a motor generator, and an engagement mechanism capable of changing the rotational speed of the rotation shaft of the motor generator by changing the engagement torque. . Specifically, the control means performs the control on the engagement mechanism when the rotational speed of the rotation shaft of the motor generator cannot be controlled by direct control on the motor generator, so that the rotation shaft of the motor generator is controlled. Control the number of revolutions. That is, the control means indirectly controls the rotation speed of the rotation shaft of the motor generator by adjusting the engagement torque in the engagement mechanism without directly controlling the rotation speed of the motor generator. As a result, for example, even when the input of the battery is limited or when the motor generator is abnormal, it is possible to appropriately control the rotational speed of the motor generator.

  In one aspect of the hybrid vehicle control device, the control means is in a state where the input of a battery that transmits and receives power to and from the motor generator is limited, and the engine speed should be reduced. In this case, the number of rotations of the rotation shaft of the motor generator is decreased by controlling the engagement mechanism.

  In this aspect, the control means is engaged in the engagement mechanism when the input of the battery is limited and when the engine speed is to be reduced (specifically, when the accelerator opening is reduced). By applying the combined torque to the motor generator, control is performed to forcibly reduce the rotational speed of the rotating shaft of the motor generator. Thereby, engine speed can be reduced appropriately. Therefore, it is possible to appropriately prevent the occurrence of a phenomenon such that the engine speed does not decrease despite the accelerator opening being reduced, and drivability can be improved.

  In another aspect of the hybrid vehicle control device, the control means controls the engagement mechanism in a case where an abnormality occurs in the motor generator and torque cannot be output. The rotational speed of the rotating shaft of the motor generator is set so as to obtain the engine torque.

  In this aspect, the control means is engaged so that the rotation speed of the rotation shaft of the motor generator is set so that an engine torque equal to or higher than a predetermined value can be obtained when an abnormality occurs in the motor generator and the torque cannot be output. Control the mechanism. Thereby, even when an abnormality occurs in the motor generator, a high engine torque can be output, and the retreat travel can be performed appropriately. For example, it is possible to properly run on a slope.

  In another aspect of the hybrid vehicle control device, the control means may be configured to output the torque before starting the engine when an abnormality occurs in the motor generator during EV traveling and torque cannot be output. By controlling the engagement mechanism, the rotational speed of the rotating shaft of the motor generator is set such that an engine rotational speed capable of causing combustion in the engine is obtained.

  In this aspect, the control means is a motor generator that can obtain an engine speed capable of causing proper combustion when an abnormality occurs in the motor generator and torque cannot be output during EV traveling. The engagement mechanism is controlled so that the number of rotations of the rotation shaft is set. As a result, even when an abnormality occurs in the motor generator during EV traveling, the engine speed can be appropriately increased, and the engine can be appropriately started. Therefore, it is possible to appropriately perform the retreat travel. Specifically, since not only battery power but also fuel can be used during retreat travel, retreat travel over a long distance is possible.

  In another aspect of the present invention, a hybrid vehicle applied to a hybrid vehicle including an engine, a motor generator, and an engagement mechanism capable of changing the rotational speed of the rotation shaft of the motor generator by changing the engagement torque. When the rotational speed of the rotation shaft of the motor generator is expected to be equal to or greater than a predetermined value, the control device performs control on the engagement mechanism to thereby control the rotational speed of the rotation shaft of the motor generator to the predetermined value. Control means for controlling to less than is provided.

  In the above hybrid vehicle control device, the control means is configured such that when the rotation speed of the rotation shaft of the motor generator is expected to be a predetermined value or more, the rotation speed of the rotation shaft of the motor generator is less than the predetermined value. The rotation speed is indirectly controlled by using the engagement torque generated by the engagement mechanism. Thereby, it can prevent appropriately that the rotation speed of the rotating shaft of a motor generator exceeds predetermined value (for example, it will become over-rotation). Therefore, it is possible to prevent the performance degradation of the motor generator and the performance degradation of the battery.

  In a preferred embodiment, the engagement mechanism is used to switch between two shift modes, a continuously variable transmission mode and a fixed transmission mode, in the hybrid vehicle.

  The hybrid vehicle control device according to the present invention is preferably applied to a hybrid vehicle including an engine, a motor generator, and an engagement mechanism capable of changing the rotation speed of the rotation shaft of the motor generator by changing the engagement torque. The Specifically, the control means performs the control on the engagement mechanism when the rotational speed of the rotation shaft of the motor generator cannot be controlled by direct control on the motor generator, so that the rotation shaft of the motor generator is controlled. Control the number of revolutions. That is, the control means indirectly controls the rotation speed of the rotation shaft of the motor generator by adjusting the engagement torque in the engagement mechanism without directly controlling the rotation speed of the motor generator. As a result, for example, even when the input of the battery is limited or when the motor generator is abnormal, it is possible to appropriately control the rotational speed of the motor generator.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Device configuration]
FIG. 1 shows a schematic configuration of a hybrid vehicle to which the vehicle control device of the present invention is applied. The example of FIG. 1 is a hybrid vehicle called a mechanical distribution type two-motor type, and includes an engine (internal combustion engine) 1, a first motor generator MG 1, a second motor generator MG 2, and a power distribution mechanism 20. An engine 1 corresponding to a power source and a first motor generator MG1 are connected to a power distribution mechanism 20. The drive shaft 3 of the power distribution mechanism 20 is connected to a second motor generator MG2 that is a power source for assisting torque (drive force) or brake force of the drive shaft 3. Further, the drive shaft 3 is connected to the left and right drive wheels 9 via a final speed reducer 8. The first motor generator MG1 and the second motor generator MG2 are electrically connected via a battery, an inverter, or an appropriate controller (see FIG. 1) or directly, and the first motor generator MG1 The second motor generator MG2 is driven by the generated electric power.

  The engine 1 is a heat engine that generates power by burning fuel, and examples thereof include a diesel engine and a gasoline engine. The first motor generator MG1 generates power mainly by receiving torque from the engine 1 and rotating, and a reaction force of torque accompanying power generation acts. By controlling the rotation speed of first motor generator MG1, the engine rotation speed of engine 1 changes continuously. Such a speed change mode is called a continuously variable speed change mode. The second motor generator MG2 is a device that assists (assists) driving force or braking force. When assisting the driving force, the second motor generator MG2 functions as an electric motor upon receipt of electric power. On the other hand, when assisting the braking force, the second motor generator MG2 functions as a generator that is rotated by the torque transmitted from the drive wheels 9 to generate electric power.

  The power distribution mechanism 20 is a so-called single pinion type planetary gear mechanism, and includes a ring gear R1, a carrier C1, and a sun gear S1. The carrier C1 holds a pinion gear CP1 that meshes with both the ring gear R1 and the sun gear S1.

  The output shaft 2 of the engine 1 is connected to the carrier C1 of the first planetary gear mechanism. One end of the rotor 11 of the first motor generator MG1 is connected to the sun gear S1 of the first planetary gear mechanism. The ring gear R1 is connected to the drive shaft 3.

  The other end of the rotor 11 of the first motor generator MG1 is connected to the lock mechanism 7. The lock mechanism 7 mainly includes a clutch 7a and an actuator 7b. The lock mechanism 7 is configured by, for example, a wet multi-plate clutch, and is configured to be able to fix the rotor 11 of the first motor generator MG1 using a frictional force. The lock mechanism 7 functions as an engagement mechanism in the present invention, and the frictional force in the lock mechanism 7 corresponds to the engagement torque.

  Specifically, in clutch 7a of lock mechanism 7, one clutch plate is fixed to a case or the like, and the other clutch plate is connected to rotor 11 of first motor generator MG1. The lock mechanism 7 is configured to be able to engage and disengage the clutch 7a using the actuator 7b. The lock mechanism 7 fixes the rotor 11 of the first motor generator MG1 and the sun gear S1 of the power distribution mechanism 20 by engaging the clutch 7a. In this case, the lock mechanism 7 functions as a friction engagement element and sets the rotation speed of the rotor 11 in the first motor generator MG1 to “0 (rpm)”. Further, the lock mechanism 7 releases the engagement of the clutch 7a, thereby releasing the rotor 11 of the first motor generator MG1 and releasing the sun gear S1 of the power distribution mechanism 20. The lock mechanism 7 controls the engagement / release of the clutch 7a based on the control signal Sig5 transmitted from the ECU 4.

  In the state where the lock mechanism 7 is disengaging the clutch 7a, the engine speed of the engine 1 is continuously changed by continuously changing the rotation speed of the first motor generator MG1, thereby realizing the continuously variable transmission mode. Is done. On the other hand, when the lock mechanism 7 is engaged with the clutch 7a, the transmission ratio determined by the power distribution mechanism 20 is in an overdrive state (that is, the engine speed of the engine 1 is smaller than the speed of the drive shaft 3). The fixed shift mode is realized.

  The power supply unit 30 includes an inverter 31, a converter 32, an HV battery 33, and a converter 34. The first motor generator MG1 is connected to the inverter 31 by a power line 37, and the second motor generator MG2 is connected to the inverter 31 by a power line 38. The inverter 31 is connected to the converter 32, and the converter 32 is connected to the HV battery 33. Further, the HV battery 33 is connected to the auxiliary battery 35 via the converter 34.

  Inverter 31 exchanges power with motor generators MG1 and MG2. During regeneration of the motor generator, the inverter 31 converts the electric power generated by the motor generators MG1 and MG2 into the direct current and supplies the direct current to the converter 32. Converter 32 converts the electric power supplied from inverter 31 to charge HV battery 33. On the other hand, when the motor generator is powered, the DC power output from the HV battery 33 is boosted by the converter 32 and supplied to the inverter 31, and then supplied to the motor generator MG 1 or MG 2 via the power line 37 or 38.

  The electric power of the HV battery 33 is converted into a voltage by the converter 34 and supplied to the auxiliary battery 35, and used for driving various auxiliary machines.

  The operation of the inverter 31, the converter 32, the HV battery 33, and the converter 34 is controlled by the ECU 4. The ECU 4 controls the operation of each element in the power supply unit 30 by transmitting the signal Sig4. A necessary signal indicating the state of each element in the power supply unit 30 is supplied to the ECU 4 as a control signal Sig4. Specifically, an SOC (State Of Charge) indicating the remaining battery capacity of the HV battery 33, an input / output limit value of the battery, and the like are supplied to the ECU 4 as a signal Sig4.

  ECU (Electronic Control Unit) 4 controls them by transmitting and receiving control signals Sig1 to Sig3 among engine 1, first motor generator MG1, and second motor generator MG2. Further, the ECU 4 controls the lock mechanism 7 by transmitting a control signal Sig 5 to the lock mechanism 7. Specifically, the ECU 4 controls the actuator 7 b of the lock mechanism 7 so as to adjust the frictional force in the clutch 7 a of the lock mechanism 7. In the present embodiment, the ECU 4 controls the lock mechanism 7 in a predetermined case, whereby the number of rotations on the rotation shaft of the first motor generator MG1 (corresponding to the number of rotations of the rotor 11). Then, it is simply called “MG1 rotational speed”). As described above, the ECU 4 functions as control means in the present invention.

[Control method]
Next, a control method performed by the ECU 4 in the present embodiment will be described. In the present embodiment, the ECU 4 controls the rotation speed (MG1 rotation speed) of the rotation shaft of the first motor generator MG1 by controlling the lock mechanism 7 in a predetermined case. That is, the MG1 rotation speed is indirectly controlled by adjusting the frictional force in the lock mechanism 7 without directly controlling the MG1 rotation speed.

(First embodiment)
A control method in the first embodiment will be described. In the first embodiment, the ECU 4 controls the MG1 rotation speed by controlling the lock mechanism 7 when the MG1 rotation speed cannot be controlled by direct control of the first motor generator MG1. More specifically, the ECU 4 indirectly adjusts the MG1 rotation speed by adjusting the frictional force in the clutch 7a of the lock mechanism 7 when the input of the HV battery 33 is limited or when the first motor generator MG1 is abnormal. Control.

(A) First Control Example Here, a first control example in the first embodiment will be described. In the first control example, the ECU 4 reduces the MG1 rotation speed by controlling the lock mechanism 7 when the input of the HV battery 33 is limited and the engine rotation speed should be decreased. That is, by generating a frictional force from the lock mechanism 7, control is performed to reduce the MG1 rotation speed by the frictional force. Specifically, the MG1 rotational speed is forcibly reduced by applying a frictional force in the lock mechanism 7 to the rotor 11 of the first motor generator MG1.

  The reason for performing such control is as follows. When the input of the HV battery 33 is limited, there are cases where the engine speed cannot be reduced appropriately even in a situation where the engine speed should be reduced (specifically, when the accelerator opening is reduced). This is because in the continuously variable transmission mode, it is necessary to reduce the MG1 rotational speed in order to reduce the engine rotational speed, but the MG1 rotational speed cannot be reduced appropriately when the input of the HV battery 33 is limited. That is, basically, when control is performed to reduce the MG1 rotation speed, power generation is performed. However, since power generation should not be performed when the input of the HV battery 33 is restricted, the MG1 rotation speed can be appropriately reduced. It is not possible.

  Thus, when the engine speed does not change even though the driver changes the accelerator opening (in other words, when the sound of the engine 1 does not change), the driver may feel uncomfortable. That is, drivability may deteriorate.

  Therefore, in the first control example, in order to prevent such deterioration in drivability, the ECU 4 performs the lock mechanism when the input of the HV battery 33 is limited and the engine speed should be reduced. 7 to control the MG1 rotational speed to be reduced by the frictional force generated from 7. That is, the ECU 4 performs control to adjust the frictional force in the lock mechanism 7 so as to be appropriately reduced to the engine speed corresponding to the accelerator opening by the driver, and to set to an appropriate MG1 speed.

  Specifically, the ECU 4 determines whether or not the input of the HV battery 33 is limited based on the signal Sig4 described above, and the engine speed should be decreased based on the output of the accelerator opening sensor or the like. It is determined whether or not. The ECU 4 supplies the control signal Sig5 to the lock mechanism 7 when the input of the HV battery 33 is restricted and when it is determined that the engine speed should be reduced. By controlling, MG1 rotation speed is reduced. Specifically, the ECU 4 performs control to reduce the MG1 rotational speed by the frictional force generated by the lock mechanism 7 so that the engine rotational speed (target rotational speed) corresponding to the accelerator opening by the driver is appropriately reduced. .

  According to such a first control example, the engine speed can be appropriately reduced when the input of the HV battery 33 is restricted and the engine speed should be reduced. Therefore, it is possible to appropriately prevent the occurrence of a phenomenon such that the engine speed does not decrease despite the accelerator opening being reduced, and drivability can be improved.

  FIG. 2 is a diagram for specifically explaining a first control example in the first embodiment. FIG. 2 shows an example of a collinear diagram showing the operation states of the first motor generator MG1, the engine 1, and the second motor generator MG2 (uniquely the drive shaft 3) in order from the left. Specifically, the up and down direction corresponds to the number of rotations, and the up direction corresponds to the forward rotation.

  A solid line A11 in FIG. 2 shows an example of a collinear diagram when the accelerator opening is set to be somewhat large. In this case, the engine speed is set to Ne11 and the MG1 speed is set to Ng11. In the first control example, when the accelerator opening is changed to a small value when the input of the HV battery 33 is limited in the state set in such a collinear diagram, the lock mechanism 7 is controlled. Specifically, the ECU 4 performs control to reduce the MG1 rotational speed from Ng11 to Ng12 by generating a frictional force from the lock mechanism 7 so that the engine rotational speed decreases from Ne11 to the target rotational speed Ne12. In this case, the alignment chart changes from a solid line A11 to a broken line A12.

(B) Second Control Example Next, a second control example in the first embodiment will be described. In the second control example, the ECU 4 adjusts the frictional force in the lock mechanism 7 when the abnormality occurs in the first motor generator MG1 and the torque cannot be output. Such MG1 rotation speed is set.

  The reason for performing such control is as follows. When the torque is not able to be output due to an abnormality / output limitation in the first motor generator MG1, if the engine torque is increased, the rotation speed of the MG1 increases, and the performance of the planetary gear or the like deteriorates There is. Therefore, in such a case, in general, the lock mechanism 7 is engaged to set the MG1 rotation speed to “0 (rpm)” for retreat travel.

  However, when the lock mechanism 7 is engaged, the engine speed tends to be low, and when the engine speed is low, the engine maximum torque tends to be low. For this reason, if the lock mechanism 7 is engaged when the first motor generator MG1 is abnormal as described above, an appropriate engine torque cannot be output, and it may not be possible to appropriately retreat on a slope. is there.

  Therefore, in the second control example, in order to ensure proper retreat travel when the first motor generator MG1 is abnormal, when the abnormality occurs in the first motor generator MG1 and torque cannot be output, the ECU 4 Controls the lock mechanism 7 so as to set the MG1 rotation speed so that an engine torque higher than a predetermined value can be obtained.

  Specifically, ECU 4 determines the abnormality of first motor generator MG1 based on control signal Sig2 described above, and when it is determined that an abnormality has occurred in first motor generator MG1 and torque cannot be output. The lock mechanism 7 is controlled by supplying a control signal Sig5 to the lock mechanism 7. Specifically, the ECU 4 adjusts the frictional force in the lock mechanism 7 so as to obtain an engine torque (corresponding to the above-described predetermined engine torque or more) necessary for performing appropriate retreat travel. Control to set the MG1 rotation speed is performed. For example, the ECU 4 performs control to increase the MG1 rotational speed by making the frictional force in the lock mechanism 7 weaker than that at the time of engagement.

  According to such a second control example, even when an abnormality occurs in the first motor generator MG1, it is possible to output a high engine torque and appropriately perform the retreat travel. For example, it is possible to properly run on a slope.

  FIG. 3 is a diagram for specifically explaining a second control example in the first embodiment. FIG. 3A shows the engine speed on the horizontal axis, the engine torque on the vertical axis, and an example of the engine maximum torque on the solid line B2. From the solid line B2, it can be seen that the maximum engine torque tends to increase as the engine speed increases.

  FIG. 3B shows an example of a collinear diagram showing operation states of the first motor generator MG1, the engine 1, and the second motor generator MG2 (uniquely the drive shaft 3) in order from the left. . Specifically, the up and down direction corresponds to the number of rotations, and the up direction corresponds to the forward rotation. A solid line A <b> 21 in FIG. 3B shows an example of a collinear diagram when the lock mechanism 7 is engaged. In the state set in such a nomograph, the engine speed is set to Ne21, and it can be seen that the engine speed is relatively low. Further, at the engine speed Ne21, as shown in FIG. 3A, the engine maximum torque is Te21, and it can be seen that the engine maximum torque is relatively low.

  In the second control example, as described above, the ECU 4 controls the lock mechanism 7 when an abnormality occurs in the first motor generator MG1 and torque cannot be output. Specifically, as shown in FIG. 3B, the ECU 4 adjusts the frictional force in the lock mechanism 7 so that the engine speed Ne22 can be obtained to obtain the engine torque necessary for performing appropriate retreat travel. As set, control is performed to set the MG1 rotation speed to Ng22. In this case, the collinear diagram indicated by the broken line A22 is set.

  As shown in FIG. 3B, the engine speed Ne22 by the control in the second control example is higher than the engine torque Ne21 set when the lock mechanism 7 is engaged. Therefore, as shown in FIG. 3A, at the engine speed Ne22, an engine maximum torque Te22 higher than the engine maximum torque Te21 at the engine speed Ne21 is obtained.

(C) Third Control Example Next, a third control example in the first embodiment will be described. In the third control example, the ECU 4 controls the lock mechanism 7 before starting to drive the engine 1 when an abnormality occurs in the first motor generator MG1 and the torque cannot be output during EV traveling. By performing this, the MG1 rotation speed is set to “0 (rpm)”. That is, by applying the frictional force in the lock mechanism 7 to the rotor 11 of the first motor generator MG1, the MG1 rotation speed is set to “0 (rpm)”. In other words, the lock mechanism 7 is engaged to fix the rotor 11 of the first motor generator MG1.

  The reason for performing such control is as follows. During EV travel, if the first motor generator MG1 has an abnormality or output limitation and cannot output torque, it tends to be difficult to increase the engine speed appropriately. For this reason, the engine 1 cannot be properly started from the EV traveling state (that is, the engine 1 cannot be properly combusted), and the retreat traveling may not be performed appropriately. .

  Therefore, in the third control example, an abnormality has occurred in the first motor generator MG1 during EV traveling so as to ensure proper retreat traveling when the abnormality occurs in the first motor generator MG1 during EV traveling. When the torque cannot be output, the ECU 4 controls the lock mechanism 7 to set the MG1 rotation speed to “0 (rpm)”. That is, the ECU 4 controls the lock mechanism 7 in order to increase it to an engine speed at which appropriate combustion can be performed (in other words, an engine speed at which the engine 1 is ignited). The MG1 rotation speed is set to “0 (rpm)”.

  Specifically, the ECU 4 determines that the first motor generator MG1 is abnormal based on the control signal Sig2, and if the first motor generator MG1 is abnormal and cannot output torque during EV traveling. When it is determined, the lock mechanism 7 is controlled by supplying a control signal Sig5 to the lock mechanism 7. Specifically, the ECU 4 controls the lock mechanism 7 to set the MG1 rotational speed to “0 (rpm)” so as to increase to an engine rotational speed at which appropriate combustion can be performed in the engine 1. That is, the ECU 4 fixes the rotor 11 of the first motor generator MG1 by engaging the lock mechanism 7.

  According to such a third control example, even when an abnormality occurs in the first motor generator MG1 during EV traveling, the engine speed can be appropriately increased, and the engine 1 is appropriately started. It becomes possible. Therefore, it is possible to appropriately perform the retreat travel. Specifically, since not only electric power of the HV battery 33 but also fuel can be used during retreat travel, retreat travel over a long distance is possible.

  FIG. 4 is a diagram for specifically explaining a third control example in the first embodiment. FIG. 4 shows an example of a collinear diagram showing the operation states of the first motor generator MG1, the engine 1, and the second motor generator MG2 (uniquely the drive shaft 3) in order from the left. Specifically, the up and down direction corresponds to the number of rotations, and the up direction corresponds to the forward rotation.

  A solid line A31 in FIG. 4 shows an example of an alignment chart during EV traveling. In this case, the engine speed is set to Ne31 which is “0 (rpm)”, and the MG1 speed is set to Ng31 which is a negative speed. In the third control example, during such EV traveling, when an abnormality occurs in the first motor generator MG1 and torque cannot be output, the ECU 4 performs control on the lock mechanism 7 to control MG1. The rotational speed is set to Ng32 which is “0 (rpm)”. That is, the ECU 4 controls the lock mechanism 7 (engages the lock mechanism 7) so that the alignment chart is in a state of, for example, a broken line A32. By such control, the engine speed increases from Ne31 to Ne32.

  In the above, an example in which the MG1 rotation speed is set to “0 (rpm)” by controlling the lock mechanism 7 has been described, but the present invention is not limited to this. Specifically, the MG1 rotation speed is not necessarily limited to “0 (rpm)” as long as the MG1 rotation speed is such that an engine rotation speed capable of appropriate combustion can be obtained. In another example, the ECU 4 can control the lock mechanism 7 so that the engine speed at which combustion can be performed appropriately is set to the MG1 speed.

(Second Embodiment)
Next, a control method in the second embodiment will be described. In the first embodiment described above, the MG1 rotation speed is controlled by the lock mechanism 7 when the MG1 rotation speed cannot be controlled by direct control on the first motor generator MG1. On the other hand, in the second embodiment, the ECU 4 controls the MG1 rotation speed by the lock mechanism 7 when the MG1 rotation speed is expected to be a predetermined value or more. Specifically, the ECU 4 uses the frictional force generated by the lock mechanism 7 so that the MG1 rotational speed is less than the predetermined value when the MG1 rotational speed is expected to be greater than or equal to the predetermined value. Control the number of revolutions indirectly. As the predetermined value in the above-described MG1 rotation speed, for example, the maximum rotation speed of first motor generator MG1 (the limit rotation speed in first motor generator MG1) is used.

  The reason for performing such control is as follows. For example, when a large force is applied to the drive shaft 3 by sudden braking or the like, the first motor generator MG1 may over-rotate. That is, the MG1 rotational speed may exceed the maximum rotational speed. In such a case, the performance of first motor generator MG1 may be degraded. Further, exceeding the input limit of the HV battery 33 may deteriorate the performance of the HV battery 33.

  Here, with reference to FIG. 5, the example of a change of MG1 rotation speed at the time of sudden braking is demonstrated. FIG. 5 shows an example of a collinear diagram showing the operation states of the first motor generator MG1, the engine 1, and the second motor generator MG2 (uniquely the drive shaft 3) in order from the left. Specifically, the up and down direction corresponds to the number of rotations, and the up direction corresponds to the forward rotation.

  A solid line A41 shows an example of a collinear chart before sudden braking is performed. In this case, the MG1 rotation speed is set to Ng41. When sudden braking is performed in the state set in the collinear diagram (when a large force is applied to the drive shaft 3 as shown by the white arrow), for example, the collinear diagram as shown by a broken line A42 To change. In this case, it can be seen that the MG1 rotational speed has increased to a rotational speed Ng42 that is larger than the maximum rotational speed Ng4 (shown by a broken line). In such a case, as described above, the performance of the first motor generator MG1 may be degraded.

  Therefore, in the second embodiment, the ECU 4 causes the lock mechanism 7 to generate the MG1 rotational speed when it is predicted that the rotation speed of the MG1 will be a predetermined value or more in order to prevent such a performance degradation of the first motor generator MG1. By using the frictional force, the MG1 rotational speed is controlled to be less than a predetermined value. That is, the ECU 4 performs control to increase the frictional force in the lock mechanism 7 so that the MG1 rotation speed is less than a predetermined value.

  Specifically, the ECU 4 determines whether or not the MG1 rotation speed is greater than or equal to a predetermined value based on a brake operation or the like by the driver, and when the MG1 rotation speed is expected to be greater than or equal to the predetermined value, the lock mechanism 7 The lock mechanism 7 is controlled by supplying a control signal Sig5. Specifically, the ECU 4 performs control to adjust the frictional force in the lock mechanism 7 so that the MG1 rotation speed is less than a predetermined value. For example, the ECU 4 obtains the MG1 rotation speed from a sensor or the like, thereby performing feedback control on the lock mechanism 7 based on the MG1 rotation speed.

  According to the control in the second embodiment described above, the MG1 rotation speed can be appropriately controlled to a rotation speed less than the predetermined value in a situation where the MG1 rotation speed can be a predetermined value or more. That is, it is possible to appropriately prevent the MG1 rotation speed from exceeding a predetermined value (over-rotation). Therefore, it is possible to prevent the performance degradation of the first motor generator MG1 and the performance degradation of the HV battery 33.

  In the above description, the example in which the lock mechanism 7 is controlled so that the MG1 rotation speed is less than the predetermined value when the MG1 rotation speed is expected to be greater than or equal to the predetermined value has been described. However, such control is performed. It is not limited to. That is, it is not limited to performing control based on the MG1 rotation speed. In another example, control can be performed based on a load applied to first motor generator MG1 instead of MG1 rotation speed. Specifically, when the load on the first motor generator MG1 is expected to be greater than or equal to a predetermined value, the ECU 4 can control the lock mechanism 7 so that the load is less than the predetermined value.

[Modification]
In the above-described embodiment, the lock mechanism 7 that fixes the rotation shaft of the first motor generator MG1 using the frictional force is shown, but the application of the present invention is not limited to this. The present invention can also be applied to a lock mechanism (engagement mechanism) that fixes the rotation shaft of first motor generator MG1 using a force other than a frictional force.

It is a figure showing the schematic structure of the hybrid vehicle concerning this embodiment. It is a figure for demonstrating the 1st example of control in 1st Embodiment. It is a figure for demonstrating the 2nd control example in 1st Embodiment. It is a figure for demonstrating the 3rd control example in 1st Embodiment. It is a figure for demonstrating the example of a change of MG1 rotation speed at the time of sudden braking.

Explanation of symbols

1 Engine 3 Drive shaft 4 ECU
7 Lock mechanism 11 Rotor 20 Power distribution mechanism 33 HV battery MG1 First motor generator MG2 Second motor generator

Claims (6)

A control device for a hybrid vehicle applied to a hybrid vehicle comprising an engine, a motor generator, and an engagement mechanism capable of changing a rotational speed of a rotation shaft of the motor generator by changing an engagement torque,
When the rotational speed of the rotating shaft of the motor generator cannot be controlled by direct control of the motor generator, the rotational speed of the rotating shaft of the motor generator is controlled by controlling the engaging mechanism. A control apparatus for a hybrid vehicle, comprising control means.   The control means controls the engagement mechanism when the input of a battery that transfers power to and from the motor generator is limited and when the engine speed should be reduced. The control apparatus for a hybrid vehicle according to claim 1, wherein the rotational speed of the rotation shaft of the motor generator is reduced.   The control means is configured to control the engagement mechanism when an abnormality occurs in the motor generator and torque cannot be output, so that the rotation shaft of the motor generator can obtain an engine torque higher than a predetermined value. The control device for a hybrid vehicle according to claim 1 or 2, wherein the control device is set to the number of revolutions.   The control means performs combustion control in the engine by controlling the engagement mechanism before starting to drive the engine when an abnormality occurs in the motor generator during EV traveling and torque cannot be output. The hybrid vehicle control device according to any one of claims 1 to 3, wherein the rotation speed of the rotation shaft of the motor generator is set such that an engine rotation speed capable of performing the operation is obtained. A control device for a hybrid vehicle applied to a hybrid vehicle comprising an engine, a motor generator, and an engagement mechanism capable of changing a rotational speed of a rotation shaft of the motor generator by changing an engagement torque,
Control for controlling the number of rotations of the rotation shaft of the motor generator to be less than the predetermined value by controlling the engagement mechanism when the number of rotations of the rotation shaft of the motor generator is expected to be a predetermined value or more A control apparatus for a hybrid vehicle, comprising: means.   The control device for a hybrid vehicle according to any one of claims 1 to 5, wherein the engagement mechanism is used to switch between two speed change modes of a continuously variable speed mode and a fixed speed change mode in the hybrid vehicle.

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