JP2011201376A - Controller for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of a hybrid vehicle without enlarging a power generator.SOLUTION: The controller of a hybrid vehicle is applied to a hybrid vehicle that includes: an engine; a power generator; a power distribution mechanism to which the engine and the power generator are connected; a driving shaft that receives an output from the power distribution mechanism; a motor for outputting torque to the driving shaft; and a brake part for fixing any rotating element of the power generation mechanism. The controller of the hybrid vehicle is provided with a control means. In reducing the rotation speed of the power generator, the control means increases torque to be output by the motor, and decreases engine torque to be output by the engine.

Description

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

  In addition to an internal combustion engine (engine), a hybrid vehicle including a motor generator that functions as an electric motor or a generator is known. In a hybrid vehicle, an internal combustion engine is operated in a highly efficient state as much as possible, while an excess or deficiency of driving force or engine brake is compensated by a motor generator.

  As an example of such a hybrid vehicle, there is a hybrid vehicle configured to be able to operate by switching between a continuously variable transmission mode and a fixed transmission ratio mode, as shown in Patent Documents 1 and 2 below. In this hybrid vehicle, an engine, a 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 generator, and an electric motor is connected to the drive shaft. In a state where the brake is released, a reaction torque corresponding to the engine torque is output to the motor generator, and the rotation speed of the 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 generator is fixed and the rotation of one rotating element in the planetary gear mechanism is prevented. As a result, the gear ratio is fixed, and the operation in the fixed gear ratio mode is executed.

  Here, in Patent Document 1, when the accelerator opening is small, the brake is engaged and the generator is fixed (that is, the fixed gear ratio mode). When the accelerator opening is large, the brake is Describes a technique for increasing the power generation amount by increasing the number of revolutions of the generator in proportion to the accelerator opening in the released state (that is, in the continuously variable transmission mode). In Patent Document 2, in a hybrid vehicle capable of switching between the fixed gear ratio mode and the continuously variable transmission mode, when switching to the fixed gear ratio mode, the magnitude of the engine torque is set to the magnitude of the reaction torque that the generator can output. In addition, a technique is described in which the rotational speed of the generator is reduced by friction of the brake while being held.

Japanese Patent Laid-Open No. 9-156387 JP 2009-234512 A

  By the way, in the hybrid vehicle described in Patent Documents 1 and 2 described above, since the brake is engaged, the generator also has a torque that reduces the rotational speed of the generator in addition to the reaction torque in the continuously variable transmission mode. It is necessary to output. When the torque for reducing the rotational speed of the generator is output by the generator, the generator may be increased in size. In this regard, Patent Documents 1 and 2 do not describe anything.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a control device for a hybrid vehicle that does not require an increase in the size of the generator.

  In one aspect of the present invention, an engine, a generator, a power distribution mechanism to which the engine and the generator are connected, a drive shaft to which an output from the power distribution mechanism is transmitted, and torque to the drive shaft Is a control device for a hybrid vehicle that is applied to a hybrid vehicle having an electric motor that outputs a brake and a brake part capable of fixing any one of the rotating elements of the power distribution mechanism, wherein the rotational speed of the generator is reduced. Control means for switching the speed change mode from the continuously variable speed change mode to the fixed speed change ratio mode by controlling the brake unit and fixing the rotating element after the control unit, and the control means comprises the rotational speed of the generator When decreasing the engine torque, the torque output from the electric motor is increased and the engine torque output from the engine is decreased.

  The control apparatus for a hybrid vehicle described above outputs an engine, a generator, a power distribution mechanism to which the engine and the generator are connected, a drive shaft to which an output from the power distribution mechanism is transmitted, and torque to the drive shaft. The present invention is applied to a hybrid vehicle having an electric motor and a brake unit capable of fixing any rotating element of the power distribution mechanism. The hybrid vehicle control device includes control means such as an ECU (Electronic Control Unit). The control means increases the torque output from the electric motor and decreases the engine torque output from the engine when the rotational speed of the generator is decreased. By doing so, it is possible to reduce the reaction torque of the generator while maintaining the driving force, and the generator torque corresponding to the reduction can be used to decrease the rotational speed of the generator. . Thereby, even if it is a case where the torque for reducing the rotation speed of a generator is output by the said generator, it can prevent that the said generator enlarges.

  In another aspect of the hybrid vehicle control device, the control means sets the torque output from the electric motor to a maximum torque that can be output. By doing so, the reaction force torque that the generator is responsible for can be minimized, and the torque that reduces the rotational speed of the generator can be increased, so that the rotational speed of the generator can be reduced. Such rotation change time can be shortened.

  In another aspect of the control apparatus for a hybrid vehicle, the control unit calculates a rotation change time required to decrease the rotation speed of the generator, and at the same time, a target rotation that is a target value of the rotation change time. A change time is calculated, and a torque output from the electric motor is adjusted so that the rotation change time becomes the target rotation change time. Thereby, drivability can be improved.

  In a preferred embodiment of the control apparatus for a hybrid vehicle, the brake unit is a lock mechanism capable of fixing the rotor of the motor generator, and the control unit switches from the continuously variable transmission mode to the fixed transmission ratio mode. First, after the rotational speed of the generator is reduced, the rotor of the generator is fixed using the lock mechanism.

  An engine, a generator, a power distribution mechanism to which the engine and the generator are connected, a drive shaft to which an output from the power distribution mechanism is transmitted, an electric motor that outputs torque to the drive shaft, and the power A control device for a hybrid vehicle applied to a hybrid vehicle having a brake portion capable of fixing any rotating element of the distribution mechanism, and controlling the brake portion after reducing the rotational speed of the generator. And a control means for switching the speed change mode from the continuously variable speed change mode to the fixed speed change ratio mode by fixing the rotating element, and the control means reduces the speed of the generator when the motor The torque output from the engine is increased and the engine torque output from the engine is decreased. Thereby, even if it is a case where the torque for reducing the rotation speed of a generator is output by the said generator, it can prevent that the said generator enlarges.

It is a figure showing the schematic structure of the hybrid vehicle concerning a 1st embodiment. It is a figure which shows an example of the alignment chart in continuously variable transmission mode and fixed gear ratio mode. It is a figure which shows an example of the alignment chart for demonstrating the torque change control which concerns on 1st Embodiment. It is a figure which shows the time chart and engine operating point which show the transmission mode switching process which concerns on 1st Embodiment. It is a figure which shows a time chart in the case of performing the shift mode switching process which does not reduce an engine torque, and an engine operating point. It is a figure which shows the time chart and engine operating point in the case of performing a transmission mode switching process along the operation line at the time of continuously variable transmission mode. It is a flowchart which shows the torque change control process which concerns on 1st Embodiment. It is a figure which shows the time chart and engine operating point which show the transmission mode switching process which concerns on 2nd Embodiment. It is a flowchart which shows the taking-out electric power determination process which concerns on 2nd Embodiment. It is a figure which shows schematic structure of the hybrid vehicle which concerns on a modification.

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

[First Embodiment]
Initially, the control method of the hybrid vehicle which concerns on 1st Embodiment of this invention is demonstrated.

  FIG. 1 shows a schematic configuration of a hybrid vehicle according to the first embodiment. 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. The engine 1 corresponding to the power source and the first motor generator MG1 are connected to the 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.

  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 includes a clutch 7a and an actuator 7b. In clutch 7a, 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 release the clutch 7a using an actuator 7b. Lock mechanism 7 engages clutch 7a to fix rotor 11 of first motor generator MG1 and to fix sun gear S1 of power distribution mechanism 20. 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 and disengagement of the clutch 7a based on the control signal Sig5 transmitted from the ECU 5.

  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 gear ratio mode is realized.

  The power supply unit 30 includes an inverter 31, a converter 32, a 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 battery 33. Further, the 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 power supplied from inverter 31 to a voltage and charges battery 33. On the other hand, when the motor generator is powered, the DC power output from the battery 33 is boosted by the converter 32 and supplied to the inverter 31, and is supplied to the motor generator MG 1 or MG 2 via the power line 37 or 38.

  The electric power of the 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 operations of the inverter 31, the converter 32, the battery 33, and the converter 34 are controlled by the ECU 4. ECU4 controls operation | movement of each element in the power supply unit 30 by transmitting control 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, SOC (State Of Charge) indicating the remaining battery capacity of the battery 33, the input / output limit value of the battery, and the like are supplied to the ECU 4 as the control signal Sig4.

  The ECU 4 sends and receives control signals Sig1 to Sig3 to and from the engine 1, the first motor generator MG1 and the second motor generator MG2, thereby controlling them and transmitting the control signal Sig5 to the lock mechanism 7. Thus, the lock mechanism 7 is controlled. For example, the ECU 4 detects the accelerator opening degree based on a control signal from an accelerator pedal (not shown) to obtain a required driving force, and the engine 1 and the first motor generator so that the driving force becomes the required driving force. MG1 and second motor generator MG2 are controlled. Further, the ECU 4 controls the lock mechanism 7 based on the required driving force and the vehicle speed, for example. Therefore, the ECU 4 functions as a control unit in the present invention.

  Next, the operation state of the hybrid vehicle in the continuously variable transmission mode and the fixed transmission ratio mode will be described with reference to FIG. FIG. 2 shows an example of an alignment chart in the continuously variable transmission mode and the fixed transmission ratio mode. 2A and 2B, the vertical direction corresponds to the rotational speed, the upward direction corresponds to the positive rotation, and the downward direction corresponds to the negative rotation. Further, the upward direction corresponds to positive torque, and the downward direction corresponds to negative torque.

  Straight lines A1a, A1b, and A1c in FIG. 2A show examples of collinear diagrams in the continuously variable transmission mode. In the continuously variable transmission mode, a reaction torque corresponding to the engine torque TKE of the engine 1 is output from the first motor generator MG1 as the torque TK1. Torque TK2 indicates the torque output from second motor generator MG2. In the continuously variable transmission mode, the engine speed of the engine 1 can be continuously controlled by increasing or decreasing the rotation speed of the first motor generator MG1. When the rotational speed of the drive shaft 3 is N1, for example, when the rotational speed of the first motor generator MG1 is sequentially changed to white circles m1, m2, and m3, the engine rotational speed of the engine 1 is White circles Ne1 (> N1), Ne2 (= N1), and Ne3 (<N1) change sequentially. That is, the engine speed of the engine 1 sequentially changes to a value higher than, equal to, and lower than the speed of the drive shaft 3. At this time, the first motor generator MG1 generates electric power and supplies electric power to the second motor generator MG2 that assists the drive shaft 3 via the inverter 31. That is, in the continuously variable transmission mode, the output from the engine 1 is directly transmitted to the drive shaft 3 via the power distribution mechanism 20 and the second motor assists the drive shaft 3 from the first motor generator MG1. It is transmitted to the drive shaft 3 through two routes: a route electrically transmitted to the motor generator MG2.

  A straight line A2 in FIG. 2B shows an example of an alignment chart in the fixed gear ratio mode. In the fixed gear ratio mode, since the lock mechanism 7 fixes the rotor 11 of the first motor generator MG1 and the sun gear S1, the gear ratio determined by the power distribution mechanism 20 is over. The drive state is fixed (that is, a state where the engine speed Ne4 of the engine 1 is smaller than the speed N1 of the drive shaft 3). At this time, since the lock mechanism 7 fixes the rotor 11 of the first motor generator MG1, the first motor generator MG1 does not function as either a generator or an electric motor. Electric power is not supplied to the motor generator MG2. Therefore, in the fixed gear ratio mode, the output from the engine 1 is transmitted to the drive shaft 3 only through a route that is directly transmitted to the drive shaft 3 via the power distribution mechanism 20.

  As can be seen from the above, the first motor generator MG1 mainly functions as a generator, and the second motor generator mainly functions as an electric motor. Therefore, in the following, unless otherwise specified, in the case of a generator, the first motor generator MG1 is indicated, and in the case of an electric motor (motor), the second motor generator MG2 is indicated. Shall.

  Hereinafter, the rotation speed and torque of the first motor generator MG1 will be referred to as MG1 rotation speed and MG1 torque, respectively, and the rotation speed and torque of the second motor generator MG2 will be referred to as MG2 rotation speed and MG2 torque, respectively. It shall be called. As can be seen from FIG. 2A, the MG1 torque is a negative torque in the continuously variable transmission mode. Therefore, when the MG1 torque is increased or decreased, it indicates that the magnitude of the torque in the negative direction increases or decreases unless otherwise specified. On the other hand, when the engine torque or MG2 torque increases or decreases, it indicates that the magnitude of the torque in the positive direction increases or decreases.

  As can be seen from FIG. 2B, in the fixed gear ratio mode, the rotor 11 of the first motor generator MG1 is fixed by the lock mechanism 7. Therefore, the ECU 4 performs the rotation change control for reducing the MG1 rotation speed to the target rotation speed when performing the shift mode switching control for switching the shift mode from the continuously variable transmission mode to the fixed gear ratio mode, and then performs the lock change control. Engagement control for fixing the rotor 11 by the mechanism 7 is performed. Here, in the hybrid vehicle in which the rotor 11 of the first motor generator MG1 is fixed by the lock mechanism 7, the target rotational speed is set to 0 rpm.

  When the rotation change control is performed, it is necessary to output a torque for reducing the MG1 rotation speed. Therefore, when the first motor generator MG1 outputs torque that decreases the MG1 rotation speed in addition to the reaction force torque, that is, when the MG1 torque is increased, the first motor generator MG1. May increase in size. On the other hand, when the MG1 rotational speed is decreased due to the friction of the clutch 7a in the lock mechanism 7, the rotational energy of the engine 1 and the first motor generator MG1 is discarded by the heat due to the friction. In this case, the greater the change in the MG1 rotational speed, the greater the rotational energy that is discarded, which may reduce fuel consumption. Further, since a large amount of heat is generated in the lock mechanism 7 in a relatively short time, the lock mechanism 7 may be increased in size by improving heat resistance. Furthermore, if the time for reducing the MG1 rotation speed is lengthened in order to reduce the amount of heat generated per unit time, appropriate drivability cannot be obtained.

  Therefore, in the hybrid vehicle control method according to the first embodiment, when the rotation change control is performed, the torque change control for increasing the MG2 torque and reducing the engine torque is performed to reduce the torque for reducing the MG1 rotation speed. We will secure it. Hereinafter, this will be specifically described with reference to FIG.

  FIG. 3 shows an example of a nomograph before torque change control and after torque change control. In FIG. 3, TKEp, TK1p, TK2p, and TKdp indicate engine torque, MG1 torque, MG2 torque, and direct torque before torque change control. Here, the direct torque is torque transmitted from the power distribution mechanism 20 to the drive shaft 3. Further, TKEa, TK1a, TK2a, and TKda indicate engine torque, MG1 torque, MG2 torque, and direct torque after torque change control. Hereinafter, a specific method of torque change control will be described.

  First, ECU 4 increases MG1 torque from torque TK1p to torque TK1a according to the state of first motor generator MG1 and the power that can be generated. Torque TK1a is a torque determined according to the state of first motor generator MG1 and the power that can be generated. As an example of a method of determining according to the state of first motor generator MG1, torque TK1a is determined using a map or the like according to the temperature of first motor generator MG1, for example. Further, as an example of a method of determining according to the electric power that can be generated by the first motor generator MG1, the torque TK1a is, for example, according to the consumable electric power of the second motor generator MG2 and the chargeable electric power of the battery 33. And determined using a map or the like. Hereinafter, the maximum torque that can be output in the torque TK1a is referred to as “generator limit torque”. In the following, as an example, the torque TK1a is set to the generator limit torque.

  Further, ECU 4 increases MG2 torque from torque TK2p to torque TK2a in accordance with the state of second motor generator MG2 and available power. Torque TK2a is the maximum torque that can be output, which is determined according to the state of second motor generator MG2 and the available power. As an example of a method of determining according to the state of second motor generator MG2, torque TK2a is determined using a map or the like, for example, according to the temperature of second motor generator MG2. Further, as an example of a method of determining according to the available power of the second motor generator MG2, the torque TK2a is, for example, the power that can be generated by the first motor generator MG1 and the power that can be taken out from the battery 33. Accordingly, it is determined using a map or the like. Hereinafter, the maximum torque TK2a that can be output is referred to as "motor limit torque".

  Then, the ECU 4 reduces the engine torque so that the sum of the direct torque and the MG2 torque satisfies the required driving force from the driver. In the example shown in FIG. 3, it is assumed that the required driving force does not change before and after torque change control. Before the torque change control is performed, the required driving force is satisfied when the MG2 torque is the torque TK2p and the direct torque is the torque TKdp. On the other hand, after the torque change control is performed, the MG2 torque changes to the torque TK2a, so that the required driving force is satisfied when the direct torque becomes the torque TKda. Therefore, the ECU 4 decreases the engine torque so that the direct torque becomes the torque TKda in order to satisfy the required driving force. That is, if the engine torque when the direct torque becomes the torque TKda is the torque TKEa, the ECU 4 reduces the engine torque from the torque TKEp to the torque TKEa. Here, the direct torque is obtained from the engine torque, the MG1 torque, the inertia mass of the engine 1 and the first motor generator MG1, and the gear ratio of the power distribution mechanism 20. Specifically, the direct torque is obtained by calculating using the following equations of motion (1) to (6) of the differential mechanism. Therefore, in order to obtain the engine torque TKEa when the direct torque becomes the torque TKda, this calculation may be performed in reverse. That is, the engine torque TKEa is based on the MG1 torque, the inertia mass of the engine 1 and the first motor generator MG1, the gear ratio of the power distribution mechanism 20, and the direct torque TKda. ) To calculate.

なお、このようにする代わりに、直達トルクとＭＧ１トルクとエンジントルクとの関係を示したマップを用いて、直達トルクがトルクＴＫｄａとなるときのエンジントルクＴＫＥａを求めるとしても良い。

Instead of doing this, the engine torque TKEa when the direct torque becomes the torque TKda may be obtained using a map showing the relationship among the direct torque, the MG1 torque, and the engine torque.

  After the torque change control is performed, an inertia torque is generated due to a decrease in the MG1 rotation speed and the engine rotation speed, so that the direct torque is transmitted to the drive shaft 3 via the power distribution mechanism 20 out of the engine torque. The inertia torque transmitted to the drive shaft 3 is added to the torque (hereinafter referred to as “engine direct torque”).

  Thus, by performing the torque change control that increases the MG2 torque and decreases the engine torque, the reaction force torque that the first motor generator MG1 takes can be decreased while maintaining the driving force, and the decrease Minute MG1 torque can be used to reduce the MG1 rotational speed.

  Next, the shift mode switching control process according to the first embodiment will be described with reference to FIG. FIG. 4A is a time chart showing the shift mode switching control process according to the first embodiment, and FIG. 4B shows the movement of the engine operating point in the shift mode switching control process according to the first embodiment. FIG. For the engine, generator, and motor shown in FIG. 4A, the torque is indicated by a solid line, and the rotational speed is indicated by a broken line (in FIGS. 5A, 6A, and 8A). the same).

  As shown in FIG. 4A, at time t1, the ECU 4 determines that the transmission mode is to be switched from the continuously variable transmission mode to the fixed transmission ratio mode based on, for example, the requested driving force and the vehicle speed (hereinafter, “ This is referred to as “engagement determination”. At this time, since the MG1 rotation speed is not the target rotation speed (here, 0 rpm), the ECU 4 performs torque change control for rotation change control for reducing the MG1 rotation speed.

  Specifically, at time t1, ECU 4 increases MG1 torque until it reaches the generator limit torque according to the state of first motor generator MG1 and the power that can be generated. The ECU 4 increases the MG2 torque to the motor limit torque according to the state of the second motor generator MG2 and the available power, and decreases the engine torque so as to satisfy the required driving force. By doing so, the reaction torque is reduced, and the MG1 rotation speed is reduced by the reduced MG1 torque. At this time, in the graph shown in FIG. 4B, the engine operating point moves from the point Pe1 (operating point in the continuously variable transmission mode) to the point Pe2.

  At this time, the drive power is composed of battery power, which is power taken out from the battery 33, rotational change power due to inertia torque due to changes in the rotational speed of the engine 1 and the first motor generator MG1, and engine power. As shown in FIG. 4B, the driving power is held at the driver required power before and after the torque change control.

  Since the MG1 rotation speed decreases from time t1 to time t2, the amount of power generated by the first motor generator MG1 also decreases. Accordingly, the ECU 4 decreases the MG2 torque and accordingly increases the engine torque in order to keep the battery power constant. At this time, in the graph shown in FIG. 4B, the engine operating point moves from the point Pe2 to the point Pe3.

  At time t2, the MG1 rotation speed becomes 0 rpm, which is the target rotation speed, and the engine torque becomes an engine torque limit that is an engine torque when the generator limit torque becomes the reaction torque. At this time, the ECU 4 controls the engagement of the lock mechanism 7 and switches from the continuously variable transmission mode to the fixed gear ratio mode. In the graph shown in FIG. 4B, the engine operating point at this time is a point Pe4 (operating point when locked).

  In this way, the transmission mode is switched from the continuously variable transmission mode to the fixed transmission ratio mode. According to the shift mode switching control described above, the battery power is kept constant.

  Here, for comparison, an example of a shift mode switching control process in the case of performing torque change control without reducing the engine torque and a shift mode switching control process in the case of performing torque change control along the operation line in the continuously variable shift mode An example will be described with reference to FIGS.

  FIG. 5A shows a time chart of the shift mode switching control process in the case of performing torque change control that does not decrease the engine torque, and FIG. 5B shows the movement of the engine operating point at that time. .

  As can be seen from FIG. 5A, in the case of performing torque change control that does not reduce the engine torque, the ECU 4 increases the MG1 torque to the generator limit torque at the time of engagement determination. The torque is not reduced. In this case, since the reaction torque cannot be reduced as compared with the case where the torque change control shown in FIG. 4 is performed, the decrease in the MG1 rotation speed becomes moderate. Therefore, compared with the time chart shown in FIG. 4A, the time required to reduce the MG1 rotation speed to the target rotation speed (here, 0 rpm) (hereinafter referred to as “rotation change time”) becomes longer. . Therefore, the torque change control shown in FIG. 4 can reduce the reaction torque compared to the torque change control that does not reduce the engine torque shown in FIG. It can be used to decrease the rotation speed, and the rotation change time required to decrease the MG1 rotation speed can be shortened.

  FIG. 6A shows a time chart of the shift mode switching control process when torque change control is performed along the operation line in the continuously variable transmission mode, and FIG. 6B shows the movement of the engine operating point at that time. It is a graph which shows.

  As can be seen from FIG. 6B, in this torque change control, control is performed so that the engine operating point moves along the operation line in the continuously variable transmission mode until the MG1 rotational speed reaches the target rotational speed. Is called.

  In this case, as shown in FIG. 6A, the MG2 torque is increased and the engine torque is decreased with the passage of time. Therefore, as the MG2 torque increases, the battery power necessary to satisfy the required drive power increases instantaneously. Therefore, the torque change control shown in FIG. 4 can keep the battery power taken out from the battery 33 constant compared to the torque change control along the operation line in the continuously variable transmission mode shown in FIG. This is preferable.

  Next, the torque change control process according to the first embodiment will be described with reference to the flowchart of FIG.

  First, in step S101, the ECU 4 calculates a torque output from the first motor generator MG1. Specifically, ECU 4 calculates the generator limit torque according to the state of first motor generator MG1 and the power that can be generated. Thereafter, the ECU 4 proceeds to the process of step S102.

  In step S102, the ECU 4 calculates the torque output from the second motor generator MG2. Specifically, ECU 4 calculates the motor limit torque according to the state of second motor generator MG2 and the available power. Thereafter, the ECU 4 proceeds to the process of step S103.

  In step S104, the ECU 4 calculates a direct torque that can satisfy the required driving force based on the required driving force and the motor limit torque. In subsequent step S105, the ECU 4 calculates the engine torque using, for example, the equation of motion of the differential mechanism, based on the direct torque and the motor limit torque obtained in step S104. Thereafter, the ECU 4 proceeds to the process of step S106.

  In step S106, the ECU 4 changes MG1 torque, MG2 torque, and engine torque. Specifically, the ECU 4 increases the MG1 torque until it reaches the generator limit torque, increases the MG2 torque until it reaches the motor limit torque, and decreases the engine torque until it reaches the engine torque obtained in step S105. Thereafter, the ECU 4 ends this control process.

  As can be seen from the above description, in the hybrid vehicle control method according to the first embodiment, the ECU 4 performs torque change control that increases the MG2 torque and decreases the engine torque when performing the rotation speed change control. I will do it. By doing in this way, the reaction force torque which 1st motor generator MG1 takes can be reduced, maintaining a driving force, and the MG1 torque of the reduction can be used for the fall of MG1 rotation speed. Thereby, even if it is a case where the torque for reducing MG1 rotation speed is output, it can prevent that 1st motor generator MG1 enlarges.

  In the first embodiment described above, the ECU 4 increases the MG2 torque to the motor limit torque, but the present invention is not limited to this. Instead of doing this, the ECU 4 can obtain the same effect as described above even if the MG2 torque is increased to a torque lower than the motor limit torque. However, if the MG2 torque is increased to the motor limit torque, the reaction torque that the first motor generator MG1 takes can be minimized, and the torque that reduces the MG1 rotational speed can be reduced. Can be increased more. That is, it is preferable to increase the MG2 torque to the motor limit torque because the time required for the rotation change control can be shortened.

[Second Embodiment]
Next, a hybrid vehicle control method according to the second embodiment will be described. The hybrid vehicle according to the second embodiment has the same configuration as the hybrid vehicle according to the first embodiment shown in FIG.

  In the hybrid vehicle control method according to the first embodiment, when changing the transmission mode from the continuously variable transmission mode to the fixed transmission ratio mode, rotation change control is performed to reduce the MG1 rotational speed to the target rotational speed. . Here, when the MG1 rotational speed is decreased, the rotational change time becomes longer as the change width of the engine rotational speed is larger. Further, as the engine torque increases, the torque that can be used to reduce the MG1 rotation speed decreases due to the increase in the reaction torque, and the rotation change time becomes longer.

  Therefore, in the hybrid vehicle control method according to the second embodiment, in addition to the hybrid vehicle control method according to the first embodiment described above, the target rotation time is calculated, and the rotation change time becomes the target rotation change time. Thus, the carry-out power from the battery 33 is determined. This will be specifically described below.

  First, a method for calculating the rotation change time will be described. Since the rotation change time is the time from the start of rotation change control to the end thereof, it is calculated based on the torque and the number of rotations after the planned torque change control. For example, when the torque change control according to the first embodiment is to be performed, the rotation change time is calculated based on the MG1 rotation speed, the generator limit torque, the motor limit torque, and the required driving force.

  Next, a method for calculating the target rotation change time will be described. The target rotation change time is determined in consideration of, for example, drivability. Specifically, the target rotation change time is determined using a map or the like according to the vehicle speed or engine power. For example, the lower the vehicle speed, the smaller the influence of road noise, wind noise, etc., so that the influence of the sound change accompanying the engine speed change becomes relatively large. Therefore, in such a case, the target rotation change time is set longer as the vehicle speed decreases in order to suppress a sudden change in sound accompanying a change in engine speed.

  The ECU 4 compares the target rotation change time with the rotation change time. If the rotation change time is shorter than the target rotation change time, the ECU 4 reduces the carry-out power from the battery 33 so that the rotation change time becomes the target rotation change time. To do. Specifically, the ECU 4 calculates the carry-out power from the battery 33 using a map showing the relationship between the value obtained by subtracting the rotation change time from the target rotation change time and the carry-out power from the battery 33.

  As the value obtained by subtracting the rotation change time from the target rotation change time increases, the ECU 4 decreases the carry-out power from the battery 33, decreases the MG2 torque, and lengthens the rotation change time. On the other hand, as the value obtained by subtracting the rotation change time from the target rotation change time becomes smaller, the ECU 4 increases the carry-out power from the battery 33 to increase the MG2 torque and shorten the rotation change time.

  The shift mode switching control process according to the second embodiment will be described with reference to FIG. FIG. 8A is a time chart showing the shift mode switching control process according to the second embodiment, and FIG. 8B shows the movement of the engine operating point in the shift mode switching control process according to the second embodiment. It is a graph to show.

  At time ta1, as described in FIG. 4, the ECU 4 performs an engagement determination to switch the speed change mode from the continuously variable speed change mode to the fixed speed change ratio mode based on, for example, the required driving force and the vehicle speed. . At this time, since the MG1 rotation speed is not the target rotation speed (here, 0 rpm), the ECU 4 performs torque change control for rotation change control for reducing the MG1 rotation speed. Here, in the second embodiment, the ECU 4 further obtains the target rotation change time based on the vehicle speed and the like, and based on the planned rotation speed and torque after torque change control, for example, the MG1 rotation speed, The rotation change time is obtained based on the generator limit torque, the motor limit torque, and the required driving force.

  In the example of the time chart of FIG. 8, since the ECU 4 determines that the rotation change time is shorter than the target rotation change time, the battery 33 corresponds to a value obtained by subtracting the rotation change time from the target rotation change time. Calculate the carry-out power from Compared with the carry-out power from the battery 33 when the MG2 torque becomes the motor limit torque, the carry-out power from the battery 33 at this time is calculated to be small. Then, as the actual torque change control, the ECU 4 sets the target torque to a torque smaller than the motor limit torque in accordance with the obtained electric power from the battery 33 when increasing the MG2 torque to the target torque. . In response to this, the ECU 4 reduces the amount of decrease in the engine torque in the actual torque change control as compared with the scheduled torque change control. Thereby, compared with the case of FIG. 4, rotation change time becomes long and approaches target rotation change time.

  At time ta2, the ECU 4 sets the MG1 rotation speed to the target rotation speed, and the engine torque becomes the engine torque limit that is the engine torque when the generator limit torque becomes the reaction torque. At this time, the ECU 4 controls the engagement of the lock mechanism 7 and switches from the continuously variable transmission mode to the fixed gear ratio mode.

  In this way, control is performed to reduce the carry-out power from the battery 33 according to the value obtained by subtracting the rotation change time from the target rotation change time, that is, by adjusting the MG2 torque after the torque change control, The rotation change time can be set as the target rotation change time regardless of conditions such as the number of rotations and torque at the time of determination.

  Next, control processing for determining the power taken out from the battery 33 will be described with reference to the flowchart of FIG.

  First, in step S201, the ECU 4 calculates a rotation change time. Specifically, the ECU 4 determines the rotation change time based on the MG1 rotation speed, the MG1 torque (for example, the generator limit torque), the MG2 torque (for example, the motor limit torque), and the required driving force after the planned torque change control. Ask for. In subsequent step S202, the ECU 4 calculates a target rotation change time based on the vehicle speed and the engine power. Thereafter, the ECU 4 proceeds to the process of step S203.

  In step S203, the ECU 4 compares the target rotation change time with the rotation change time, and determines whether or not the rotation change time is shorter than the target rotation change time. If the ECU 4 determines that the rotation change time is shorter than the target rotation change time (step S203: Yes), the ECU 4 proceeds to the process of step S204. On the other hand, when the ECU 4 determines that the rotation change time is not shorter than the target rotation change time, that is, the rotation change time is equal to or longer than the target rotation change time (step S203: No), this control process is performed. finish.

  In step S204, the ECU 4 calculates the carry-out power from the battery 33 using, for example, a map or the like according to the value obtained by subtracting the rotation change time from the target rotation change time, and actually calculates the carry-out power according to the calculated carry-out power. MG2 torque after the torque change control is determined, and this control process is terminated.

  As can be seen from the above description, in the hybrid vehicle control method according to the second embodiment, the target rotation change time is compared with the rotation change time, and when the rotation change time is shorter than the target rotation change time. In order to make the rotation change time equal to the target rotation change time, control is performed to reduce the carry-out power from the battery 33 according to the value obtained by subtracting the rotation change time from the target rotation change time, that is, the MG2 torque is adjusted. Take control. Accordingly, the rotation change time can be set to the target rotation change time regardless of conditions such as the rotation speed and torque at the time of engagement determination, and drivability can be improved.

[Modification]
In addition, this invention is not limited to the above-mentioned embodiment, It can implement with a various form within the range of the summary of this invention.

  For example, in the above-described embodiment, the power distribution mechanism 20 is a single pinion type planetary gear mechanism, but is not limited thereto. Instead, it may be a double pinion type planetary gear mechanism. That is, the carrier C1 is configured to mesh with the inner pinion gear configured to mesh with the sun gear S1 and the inner pinion gear and the ring gear R1 instead of holding the pinion gear CP1 meshed with both the ring gear R1 and the sun gear S1. It is also possible to hold the outer pinion gear. Further, the pinion gear CP1 may be a pinion gear with a step.

  Further, the hybrid vehicle mechanism to which the present invention can be applied is not limited to a mechanism that realizes the fixed gear ratio mode by locking the rotor of the first motor generator MG1. Instead, for example, as shown in FIG. 10 below, the present invention is applicable to a mechanism that realizes the fixed gear ratio mode by fixing any one of the rotating elements of the power distribution mechanism 20 with a brake. It is possible to apply.

  FIG. 10 is a skeleton diagram showing a schematic configuration of a hybrid vehicle according to a modification. 10, components having the same functions as those of the hybrid vehicle shown in FIG. 1 are denoted by the same reference numerals as those in FIG.

  In the hybrid vehicle according to the modification, the engine 1 and the first motor generator MG1 are connected to the power distribution mechanism 20. A second motor generator MG <b> 2 is connected to the drive shaft 3 via the transmission unit 6 on the drive shaft 3 of the power distribution mechanism 20.

  The power distribution mechanism 20 is a mechanism that distributes the engine torque of the engine 1 to the first motor generator MG1 and the drive shaft 3, and is configured to generate a differential action. Specifically, the engine 1 is connected to the first rotating element among the four rotating elements that are provided with a plurality of sets of differential mechanisms and have a differential action, and the first motor generator MG1 is connected to the second rotating element. Are coupled, and the drive shaft 3 is coupled to the third rotating element. The fourth rotating element can be fixed by the brake portion 7bk.

  The power distribution mechanism 20 is configured by combining two planetary gear mechanisms. The first planetary gear mechanism includes a ring gear R1, a carrier C1, and a sun gear S1. The second planetary gear mechanism is a double pinion type, and includes a ring gear R2, a carrier C2, and a sun gear S2.

  The output shaft 2 of the engine 1 is connected to the carrier C1 of the first planetary gear mechanism, and the carrier C1 is connected to the ring gear R2 of the second planetary gear mechanism. These constitute the first rotating element. The rotor 11 of the first motor generator MG1 is connected to the sun gear S1 of the first planetary gear mechanism, and these constitute a second rotating element.

  The ring gear R1 of the first planetary gear mechanism and the carrier C2 of the second planetary gear mechanism are connected to each other and to the drive shaft 3. These constitute the third rotating element. The sun gear S2 of the second planetary gear mechanism is connected to the rotation shaft 29 and constitutes a fourth rotation element together with the rotation shaft 29. The rotating shaft 29 can be fixed by the brake portion 7bk. The brake unit 7bk is controlled by the ECU 4.

  In a state where the brake unit 7bk does not fix the fourth rotation element, the engine speed of the engine 1 is continuously changed by continuously changing the rotation speed of the first motor generator MG1, so that the continuously variable transmission is performed. The mode is realized. On the other hand, in a state where the brake unit 7bk fixes the fourth rotation element, the transmission gear ratio determined by the power distribution mechanism 20 is in the overdrive state (that is, the rotation speed output from the engine 1 is the rotation of the drive shaft 3). In a state smaller than the number), and a fixed gear ratio mode is realized.

  The present invention can also be applied to a hybrid vehicle according to a modification. That is, when switching the speed change mode from the continuously variable speed change mode to the fixed speed change ratio mode, the reaction torque that the first motor generator MG1 takes can be reduced by increasing the MG2 torque and decreasing the engine torque. The reduced MG1 torque can be used to decrease the MG1 rotation speed. At this time, the ECU 4 reduces the MG1 rotation speed with the MG1 rotation speed when the rotation speed of the fourth rotation element is “0” as the target rotation speed. Further, at this time, the target rotation change time is compared with the rotation change time. If the rotation change time is shorter than the target rotation change time, the target rotation is set so that the rotation change time becomes the target rotation change time. Control may be performed to reduce the carry-out power from the battery in accordance with a value obtained by subtracting the rotation change time from the change time. As a result, the rotation change time can be set to the target rotation change time, and drivability can be improved.

  As can be seen from the above description, in essence, a continuously variable transmission mode in which the reaction force torque is output from the motor generator and the rotational speed ratio between the rotational speed of the engine and the rotational speed of the drive shaft continuously changes, The hybrid vehicle control method of the present invention can be applied to any hybrid vehicle having a fixed gear ratio mode in which the rotation speed ratio is fixed by fixing any of the rotating elements in the power distribution mechanism. Is possible.

MG1, MG2 Motor generator 1 Engine 7 Lock mechanism 20 Power distribution mechanism 4 ECU

Claims (4)

An engine, a generator, a power distribution mechanism to which the engine and the generator are connected, a drive shaft to which an output from the power distribution mechanism is transmitted, an electric motor that outputs torque to the drive shaft, and the power A control device for a hybrid vehicle applied to a hybrid vehicle having a brake part capable of fixing any rotating element of the distribution mechanism,
Control means for switching the speed change mode from the continuously variable speed change mode to the fixed speed change ratio mode by fixing the rotating element by controlling the brake unit after reducing the rotational speed of the generator;
The control means increases the torque output from the electric motor and decreases the engine torque output from the engine when reducing the rotational speed of the generator. .   The control device for a hybrid vehicle according to claim 1, wherein the control means sets the torque output from the electric motor to a maximum torque that can be output.   The control means calculates a rotation change time required to reduce the rotation speed of the generator, calculates a target rotation change time that is a target value of the rotation change time, and the rotation change time is the target rotation. The hybrid vehicle control device according to claim 1, wherein a torque output from the electric motor is adjusted so as to be a change time. The brake unit is a lock mechanism capable of fixing the rotor of the motor generator,
The control means, when switching from the continuously variable transmission mode to the fixed transmission ratio mode, lowers the rotational speed of the generator and then fixes the rotor of the generator using the lock mechanism. The hybrid vehicle control device according to any one of claims 3 to 4.

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