JP5119023B2 - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a hybrid vehicle for preventing a power generator from being enlarged. <P>SOLUTION: The control device of a hybrid vehicle is applied to a hybrid car equipped with: a variable shift mode in which reaction torque is output by a motor generator according to the engine torque of an engine, and the ratio of the engine rotation speed of the engine to the rotation speed of a driving shaft is continuously changed; and a fixed shift mode in which reaction torque is not output by the motor generator, but the ratio of the rotation speeds is fixed. The control device of the hybrid vehicle is provided with a control means. The control means switches the shift mode from the variable shift mode to the fixed shift mode when the reaction torque corresponding to the engine torque exceeds torque upper limit which can be output by a motor generator. Thus, it is possible to prevent the motor generator from being enlarged, and to improve fuel consumption. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

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 mode, as shown in Patent Document 1 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 transmission ratio is fixed, and the operation in the fixed transmission mode is executed. In Patent Document 1, when the accelerator opening is small, the brake is engaged, and the generator is fixed (that is, in the fixed transmission mode). When the accelerator opening is large, the brake is released. A technique for increasing the amount of power generation by increasing the number of revolutions of the generator in proportion to the accelerator opening (that is, as a continuously variable transmission mode) is described.

Japanese Patent Laid-Open No. 9-156387

  By the way, in patent document 1, although it is set as the continuously variable transmission mode in a medium speed to a high speed range, about the case where the reaction force torque corresponding to an engine torque exceeds the torque upper limit which can be output of a generator. Is not considered. In such a case, if the reaction force torque corresponding to the engine torque is output to the motor generator, the generator becomes larger and the fuel consumption deteriorates.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a control device for a hybrid vehicle that can suppress an increase in the size of a generator and improve fuel efficiency. .

In one aspect of the present invention, an engine, a motor generator, a power distribution mechanism to which the engine and the motor generator are coupled, and a drive shaft to which an output from the power distribution mechanism is transmitted, As a mode, a continuously variable transmission that outputs a reaction torque from the motor generator corresponding to the engine torque of the engine and continuously changes the rotation speed ratio between the engine rotation speed of the engine and the rotation speed of the drive shaft. A hybrid vehicle control device applied to a hybrid vehicle having a mode and a fixed speed change mode for fixing the rotation speed ratio without outputting a reaction torque from the motor generator, If the corresponding reaction force torque exceeds the upper limit of torque that can be output by the motor generator, it is A control means to the fixed speed change mode switching the shift mode, the hybrid vehicle, in the case of the continuously variable shift mode, the electric power generated by the motor generator, an assist motor-generator that outputs a torque to the drive shaft And when the shift mode is set to the fixed shift mode and the control means determines that there is an acceleration request, the control means increases the engine torque and exceeds the maximum engine torque of the engine. When requested, the engine torque output from the engine is reduced to the engine torque corresponding to the reaction torque that can be output from the motor generator, and then the engine speed is increased. At the same time, the assist motor generator is connected to the drive shaft. By outputting the click switches the transmission mode from the fixed speed change mode to the stepless speed change mode.

The hybrid vehicle control device includes an engine, a motor generator, a power distribution mechanism to which the engine and the motor generator are coupled, and a drive shaft to which an output from the power distribution mechanism is transmitted, As a speed change mode, a reaction force torque is output from the motor generator corresponding to the engine torque of the engine, and the speed ratio between the engine speed of the engine and the speed of the drive shaft is continuously changed. The present invention is applied to a hybrid vehicle having a speed change mode and a fixed speed change mode in which the rotation speed ratio is fixed without outputting reaction force torque from the motor generator. The motor generator is, for example, a first motor generator. The control device for the hybrid vehicle includes control means such as an ECU (Electronic Control Unit). When the reaction torque corresponding to the engine torque exceeds the upper limit of the torque that can be output by the motor generator, the control means switches the shift mode from the continuously variable transmission mode to the fixed transmission mode. By doing in this way, the enlargement of the said motor generator can be suppressed and a fuel consumption can be improved.
Further, when the shift mode is set to the fixed shift mode, the control means increases the engine torque when determining that there is an acceleration request. By doing so, it is possible to improve the fuel efficiency as compared with the case of the continuously variable transmission mode, and it is not necessary to increase the engine speed in order to increase the output, thereby improving drivability. be able to.
In addition, when there is a driving force request exceeding the maximum engine torque of the engine, the control means determines the magnitude of the engine torque output from the engine as the magnitude of the engine torque corresponding to the reaction force torque that can be output from the motor generator. Then, the engine speed is increased and torque is output from the assist motor generator to the drive shaft, thereby switching the shift mode from the fixed shift mode to the continuously variable shift mode. The assist motor generator is, for example, a second motor generator. In this way, the shift mode can be switched from the fixed shift mode to the continuously variable shift mode, and a part of the engine output can be obtained as the output torque from the assist motor generator. As a result, it is possible to smoothly output a desired driving force during high-speed traveling, thereby improving drivability.

  In a preferred embodiment of the hybrid vehicle control device, the hybrid vehicle includes a lock mechanism capable of fixing the rotor of the motor generator, and the control means switches from the continuously variable transmission mode to the fixed transmission mode. The rotor of the motor generator is released when the rotor of the motor generator is fixed and when switching from the fixed transmission mode to the continuously variable transmission mode.

  In a preferred embodiment of the hybrid vehicle control device, the engine is a diesel engine.

  An engine, a motor generator, a power distribution mechanism to which the engine and the motor generator are coupled, and a drive shaft to which an output from the power distribution mechanism is transmitted. In response to the above, the motor generator outputs a reaction force torque, and continuously changes the rotation speed ratio between the engine rotation speed of the engine and the rotation speed of the drive shaft; A control device for a hybrid vehicle applied to a hybrid vehicle having a fixed speed change mode for fixing the rotation speed ratio without outputting force torque, wherein a reaction force torque corresponding to the engine torque is applied to the motor If the upper limit of the torque that can be output by the generator is exceeded, the continuously variable transmission mode is changed to the fixed transmission mode. A control means for switching the speed mode. Thereby, the enlargement of the motor generator can be suppressed, and fuel consumption can be improved.

  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 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 / release 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 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. 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 HV 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. At this time, the ECU 4 controls the lock mechanism 7 based on the engine torque of the engine 1 and the reaction torque of the first motor generator MG1. Therefore, the ECU 4 functions as a control unit in the present invention.

(Control method)
Next, a hybrid vehicle control method according to the present embodiment will be described.

  First, the operation state of the hybrid vehicle in the continuously variable transmission mode and the fixed transmission 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 mode. 2A and 2B, the vertical direction corresponds to the rotational speed, and the upward direction corresponds to the positive rotation.

  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 speed change mode. In the fixed speed change mode, the lock mechanism 7 fixes the rotor 11 of the first motor generator MG1 and the sun gear S1. Therefore, the speed ratio determined by the power distribution mechanism 20 is overdrive. The state is fixed (ie, the state in which 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 speed change 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.

  Here, when the engine 1 is an engine capable of outputting a relatively high torque, such as a diesel engine, for example, the engine torque of the engine 1 tends to be relatively large from a medium speed to a high speed region. Therefore, when the speed change mode is changed to the continuously variable speed mode from the medium speed to the high speed range, the reaction torque corresponding to the engine torque may exceed the upper limit of the torque that can be output by the first motor generator MG1. There is. Here, even if the engine torque of the engine 1 becomes relatively large, if the reaction torque is to be output to the first motor generator MG1 correspondingly, the first motor Since it is necessary to increase the power generation capacity of the generator MG1, the first motor generator MG1 is increased in size.

  In the continuously variable transmission mode, a route directly transmitted to the drive shaft 3 via the power distribution mechanism 20, a route electrically transmitted from the first motor generator MG1 to the second motor generator MG2, The output from the engine 1 is transmitted to the drive shaft 3 through these two routes. Therefore, even when the first motor generator MG1 is enlarged, when the speed change mode is set to the continuously variable speed mode from the medium speed to the high speed range, the fixed speed change mode is set. Compared with, transmission loss becomes large and fuel consumption deteriorates.

  Therefore, in the hybrid vehicle control device according to the present embodiment, the ECU 4 determines that the reaction torque corresponding to the engine torque of the engine 1 exceeds the upper limit of the torque that can be output by the first motor generator MG1. The shift mode is switched from the step shift mode to the fixed shift mode. Hereinafter, this will be specifically described with reference to FIG.

  FIG. 3 is a diagram showing the operating point of the engine 1 when the engine 1 is a diesel engine. The vertical axis shows the engine torque and the horizontal axis shows the engine speed. FIG. 3 shows operation lines (hereinafter referred to as “CVT operation lines”) Lcv and equal power lines Lp1 to Lp3 of the engine 1 in the case of the continuously variable transmission mode. Here, specifically, the CVT operation line Lcv is defined so as to be optimal from the viewpoint of improving fuel efficiency and suppressing NOx emission. In addition, a region set in the fixed transmission mode as an operating point region is shown as a fixed transmission mode region ArD.

  As shown in FIG. 3, on the CVT operation line Lcv, the engine torque of the engine 1 has a maximum value of the torque TKec. That is, torque TKec indicates the engine torque corresponding to the upper limit reaction force torque that can be output from first motor generator MG1 in the case of continuously variable transmission mode. In other words, when the engine torque of engine 1 exceeds torque TKec, the reaction torque corresponding to the engine torque exceeds the upper limit of the torque that can be output by first motor generator MG1. Hereinafter, the torque TKec is sometimes referred to as “reaction force upper limit engine torque”. In FIG. 3, the torque TKes indicates the maximum value of the engine torque of the engine 1 (hereinafter referred to as “maximum engine torque”). In an engine such as a diesel engine that can output a high torque, as shown in FIG. 3, the maximum engine torque TKes is larger than the reaction force upper limit engine torque TKec.

  As shown in FIG. 3, a region where the engine torque of the engine 1 exceeds the reaction force upper limit engine torque TKec is a fixed speed change mode region ArD. The ECU 4 sets the fixed transmission mode when the operating point of the engine 1 is located in the fixed transmission mode area ArD. This fixed transmission mode region ArD is a region in which fuel consumption can be improved in the fixed transmission mode compared to the case of the continuously variable transmission mode. Accordingly, in the case of the continuously variable transmission mode, when the engine torque exceeds the reaction force upper limit engine torque TKec, for example, when the operating point is moved from the point Pc1 to the point Ps1, the ECU 4 performs the fixed transmission from the continuously variable transmission mode. The shift mode is switched to the mode. Thus, when the engine torque of the engine 1 exceeds the reaction force upper limit engine torque TKec, there is no need to output the reaction torque corresponding to the engine torque of the engine 1 to the first motor generator MG1. The first motor generator MG1 does not need to be increased in size, and the fuel efficiency can be improved.

  In the example shown in FIG. 3, a part of the region of the operating point where the engine torque of the engine 1 is smaller than the reaction force upper limit engine torque TKec is also set as the region ArD. In this region, even when the engine torque of the engine 1 is smaller than the reaction force upper limit engine torque TKec, the fuel consumption can be improved in the fixed transmission mode compared to the case of the continuously variable transmission mode. It is an area. Therefore, for example, when the operating point is located at the point Pc3 as the continuously variable transmission mode on the equal power line Lp3, and when the operating point is located at the point Ps3 as the fixed transmission mode, the operating point is set as the fixed transmission mode. The fuel efficiency can be improved when is located at the point Ps3.

  As described above, the maximum engine torque TKes of the engine 1 is larger than the reaction force upper limit engine torque TKec. Therefore, in the present embodiment, when there is an acceleration request in the state of the fixed speed change mode, the ECU 4 increases the engine torque of the engine 1 while maintaining the fixed speed change mode, instead of switching to the continuously variable speed change mode. I will do it. As a result, fuel efficiency can be improved compared to the case of switching to the continuously variable transmission mode, and it is not necessary to increase the engine speed in order to increase the output, thereby improving drivability. it can.

  Here, a case where there is a required driving force exceeding the maximum engine torque TKes of the engine 1 in the state of the fixed speed change mode will be described.

  When there is a required driving force that exceeds the maximum engine torque TKes of the engine 1, the ECU 4 switches the transmission mode from the fixed transmission mode to the continuously variable transmission mode. For example, when the operating point is at the point Ps1 in the state of the fixed speed change mode and there is a required driving force that exceeds the maximum engine torque TKes of the engine 1, the ECU 4 sets the operating point from the point Ps1. Move to Pc1 and switch to continuously variable transmission mode. In this way, a part of the output of the engine 1 can be obtained as the output torque of the second motor generator MG2, so that a desired driving force can be smoothly output during high-speed driving, and the driver Can be improved.

  However, when there is a required driving force that exceeds the maximum engine torque TKes of the engine 1, when the constant shift mode is always switched to the continuously variable transmission mode, the shift mode is frequently switched. This is not preferable from the viewpoint of drivability.

  Therefore, when there is a required driving force that exceeds the maximum engine torque TKes of the engine 1, the ECU 4 does not always switch from the fixed transmission mode to the continuously variable transmission mode, but instead of the maximum engine torque TKes of the engine 1. Based on the torque that can be output from the second motor generator MG2, it is determined whether or not the required driving force can be satisfied in the state of the fixed speed change mode. It is also possible to switch to the mode.

  Specifically, first, the ECU 4 obtains the required driving force based on the accelerator opening and the like, and the required driving force based on the maximum engine torque TKes of the engine 1 and the torque that can be output from the second motor generator MG2. It is determined whether it is possible to satisfy the above. For example, the ECU 4 determines whether or not the value obtained by subtracting the maximum engine torque TKes from the required driving force is equal to or lower than the upper limit of the torque that can be output from the second motor generator MG2, and the second motor generator MG2 When it is determined that the torque is less than the upper limit of the torque that can be output, the required driving force can be satisfied by the maximum engine torque TKes of the engine 1 and the torque that can be output by the second motor generator MG2. Judge that there is.

  If the ECU 4 determines that the required driving force can be satisfied by the maximum engine torque TKes of the engine 1 and the torque that can be output from the second motor generator MG2, the ECU 4 does not switch to the continuously variable transmission mode. In addition, while maintaining the fixed speed change mode, the engine torque of the engine 1 is set to the maximum engine torque TKes, and the lack of driving force is assisted by the output torque of the second motor generator MG2. At this time, the electric power stored in advance in the HV battery 33 is supplied to the second motor generator MG2.

  In other words, the ECU 4 is fixed only when it is determined that the required driving force cannot be satisfied by the maximum engine torque TKes of the engine 1 and the torque that can be output from the second motor generator MG2. The shift mode is switched to the continuously variable mode. By doing in this way, it is possible to prevent the shift mode from frequently switching, and it is possible to improve drivability.

  Here, in the above-described embodiment, the diesel engine is used as the engine 1, but the present invention is not limited to this. In short, the present invention can be applied to any engine in which the maximum engine torque TKes is larger than the reaction force upper limit engine torque TKec. Examples of the engine having such properties include a diesel engine, a gasoline engine with a supercharger, a gasoline engine with a large displacement, and the like. Accordingly, the engine 1 of the hybrid vehicle according to the present embodiment is not limited to a diesel engine, and may instead be a gasoline engine with a supercharger or a gasoline engine with a large displacement.

(Transmission mode switching method)
Next, the shift mode switching method will be specifically described.

  First, the case where the transmission mode is switched from the fixed transmission mode to the continuously variable transmission mode will be described using an example in which the operating point in FIG. 3 is moved from the point Ps2 to the point Pc2. As shown in FIG. 3, when the operating point is located at the point Ps2, the engine torque and engine speed of the engine 1 are the maximum engine torque TKes and the rotation speed Nes, and the speed change mode is the fixed speed change mode. It has become. When the operating point is located at the point Pc2, the engine torque and engine speed of the engine 1 are the reaction force upper limit engine torque TKec and the rotation speed Nec, and the shift mode is the continuously variable transmission mode.

  FIG. 4 shows an example of an alignment chart in the fixed speed change mode and the continuously variable speed change mode. In FIG. 4, the up and down direction corresponds to the number of rotations, and the up direction corresponds to the forward rotation.

  A straight line As1 is a collinear diagram when the operating point in FIG. 3 is located at the point Ps2. Since the operating point in FIG. 3 is located at the point Ps2, the engine torque of the engine 1 is the torque TKes, and the engine rotational speed is the rotational speed Nes (see FIG. 3). At this time, since the fixed speed change mode is set, the rotation speed of the first motor generator MG1 is zero. At this time, the rotation speed of second motor generator MG2 (the rotation speed of drive shaft 3) is Nmg2, and is kept constant before and after the shift mode is switched. In the fixed speed change mode, it is assumed that the driving force assist by the second motor generator MG2 is not performed.

  A straight line Ac1 shows a collinear diagram when the operating point in FIG. 3 is located at the point Pc2. Since the operating point in FIG. 3 is located at the point Pc2, the engine torque of the engine 1 is the torque TKec, and the engine rotational speed is the rotational speed Nec (see FIG. 3). At this time, since the continuously variable transmission mode is set, the rotation speed of the first motor generator MG1 is the rotation speed Nmg1. The rotational speed Nmg1 is defined by the engine rotational speed Nec of the engine 1 and the rotational speed (rotational speed of the drive shaft 3) Nmg2 of the second motor generator MG2. Further, reaction force torque TKmg1 corresponding to engine torque TKec of engine 1 is output from first motor generator MG1.

  FIGS. 5 and 6 show examples of changes in operation of the engine and the motor generator with respect to time when switching from the fixed transmission mode to the continuously variable transmission mode, respectively. Specifically, in FIG. 4 described above, a case where the collinear diagram changes from the straight line As1 to the straight line Ac1 is shown.

  First, the operation of the engine and motor generator shown in FIG. 5 will be described. In the example shown in FIG. 5, when switching from the fixed speed change mode to the continuously variable speed change mode, the operating point of the engine 1 is changed from the point Ps2 to the point Pc2 along the equal power line Lp2.

  FIG. 5A shows changes in the torque of the engine 1 (engine torque) and the rotational speed (engine rotational speed) with respect to time. FIG. 5B shows changes in the output torque and rotation speed of the first motor generator MG1 with respect to time. FIG. 5C shows changes with respect to time of the output torque and the rotation speed of the second motor generator MG2. 5 (a) to 5 (c), the alternate long and short dash line indicates a change in torque over time, and the solid line indicates a change in rotation speed over time.

  Until the time t1, the clutch 7a is engaged in the fixed transmission mode, that is, the lock mechanism 7. Therefore, until time t1, the rotor 11 of the first motor generator MG1 is fixed, so the output torque and the rotational speed of the first motor generator MG1 are 0 (see FIG. 5B). Further, until time t1, the engine torque and the engine speed of the engine 1 are the torque and the speed corresponding to the operating point Ps2 in FIG. That is, the engine torque of the engine 1 is the maximum engine torque TKes, and the engine rotational speed of the engine 1 is the rotational speed Nes (see FIG. 5A). Further, in the example shown in FIG. 5, the driving force is not assisted by the second motor generator MG2 because the fixed speed change mode is set until time t1. Therefore, the output torque of second motor generator MG2 is zero until time t1. Note that the rotation speed Nmg2 of the second motor generator MG2 is equal to the rotation speed of the drive shaft 3, and is kept constant while the shift mode is switched (see FIG. 5C).

  From time t1 to time t2, the engine torque of the engine 1 is controlled to gradually decrease from the torque TKes, and the engine speed of the engine 1 is controlled to gradually increase from the rotation speed Nes (FIG. 5 (a )reference). Specifically, in FIG. 3, the operating point is controlled to move from the point Ps2 to the point Pc2 along the equal power line Lp2.

  Further, from time t1 to time t2, the clutch 7a in the lock mechanism 7 is released, but is not completely released. That is, the lock mechanism 7 is controlled so that the clutch plates of the clutch 7a slide, that is, the clutch 7a is in a state close to a so-called half-clutch. Therefore, from time t1, in order to receive the engine torque of engine 1, first motor generator MG1 starts to output reaction force torque TKmg1. Further, since the lock mechanism 7 is controlled so that the clutch plates of the clutch 7a slide with each other, a frictional force is generated between the clutch plates of the clutch 7a. Therefore, from time t1, the rotation speed of first motor generator MG1 gradually increases from 0 (see FIG. 5B). Thus, by generating a frictional force between the clutch plates in the clutch 7a and gradually increasing the rotational speed of the first motor generator MG1 from 0, the engine rotational speed of the engine 1 increases rapidly, so-called blowing. The rise can be prevented.

  Further, in order to keep the driving force constant from time t1 to time t2, the output torque of the second motor generator gradually increases from 0 as the engine torque of the engine 1 decreases from the torque TKes. It is controlled (see FIG. 5C). That is, from time t1, the second motor generator MG2 starts assisting the driving force. At this time, the electric power stored in advance in the HV battery 33 is supplied to the second motor generator MG2.

  After the time t2, the lock mechanism 7 is controlled so that the clutch 7a is completely released, and enters the continuously variable transmission mode. At this time, the engine torque of the engine 1 is the torque TKec, and the engine speed of the engine 1 is Nec (see FIG. 5A). That is, in FIG. 3, the operating point reaches the point Pc2. The rotational speed of first motor generator MG1 rises completely and reaches rotational speed Nmg1 (see FIG. 5B). The rotational speed Nmg1 is a rotational speed defined by the engine rotational speed Nes of the engine 1 and the rotational speed (rotational speed of the drive shaft 3) Nmg2 of the second motor generator MG2 as described in FIG. At this time, the second motor generator MG2 outputs the torque TKmg2 by the electric power generated in the first motor generator MG1. That is, the power supplied to the second motor generator is completely covered by the power generated in the first motor generator MG1.

  FIG. 5D shows the change of the ratio of each torque in the driving force with respect to time. In FIG. 5D, “torque transmitted directly from the engine” indicates the torque of the engine torque of the engine 1 that is directly transmitted to the drive shaft 3 via the power distribution mechanism 20. The “torque transmitted from the engine through the electric path” is the torque of the engine torque of the engine 1 that is electrically transmitted from the first motor generator MG1 to the second motor generator MG2, that is, the first torque The torque output from the second motor generator MG2 to the drive shaft 3 by the electric power generated in one motor generator MG1 is shown. The “torque by the stored power from the HV battery” indicates the torque output from the second motor generator MG2 to the drive shaft 3 by the power stored in the HV battery 33 in advance.

  As shown in FIG. 5D, since the second motor generator MG2 starts to output torque to the drive shaft 3 from time t1 to t2, at this time, the electric power accumulated in advance in the HV battery 33 is the second To the motor generator MG2. However, at this time, the first motor generator MG1 outputs the reaction force torque TKmg1, and the rotational speed also gradually increases. Therefore, the HV battery 33 is charged by the electric power generated in the first motor generator MG1. Therefore, with the passage of time, the power supplied to second motor generator MG2 is gradually covered by the power generated in first motor generator MG1. After time t2, first motor generator MG1 outputs reaction force torque TKmg1, and the rotation speed becomes rotation speed Nmg1, and the electric power supplied to the second motor generator is generated in first motor generator MG1. The amount of power stored completely in the HV battery 33 is hardly reduced by the generated power.

  By using the method described above with reference to FIG. 5, the shift mode can be switched from the fixed shift mode to the continuously variable shift mode while keeping the driving force constant, and a part of the output of the engine 1 is changed to the second. Can be obtained as an output torque by the motor generator MG2. As a result, it is possible to smoothly output a desired driving force during high-speed traveling, thereby improving drivability.

  Next, operations of the engine and motor generator shown in FIG. 6 will be described. In the example shown in FIG. 6, when switching from the fixed speed change mode to the continuously variable speed change mode, the magnitude of the engine torque of the engine 1 is set to the engine torque corresponding to the reaction torque that can be output from the first motor generator MG1. After reducing to the magnitude, the engine speed of the engine 1 is increased.

  FIG. 6A shows changes in the torque of the engine 1 (engine torque) and the rotational speed (engine rotational speed) with respect to time. FIG. 6B shows changes in the output torque and rotation speed of the first motor generator MG1 with respect to time. FIG. 6C shows changes with time in the output torque and the rotational speed of the second motor generator MG2. 6 (a) to 6 (c), the alternate long and short dash line indicates the time change of the torque, and the solid line indicates the time change of the rotational speed.

  Until the time t1, the clutch 7a is engaged in the fixed transmission mode, that is, the lock mechanism 7. Therefore, until time t1, since the rotor 11 of the first motor generator MG1 is fixed, the output torque and the rotational speed of the first motor generator MG1 are 0 (see FIG. 6B). Until time t1, the engine torque and the rotational speed of the engine 1 are the torque TKes and the rotational speed Nes corresponding to the operating point Ps2 in FIG. 3 (see FIG. 6A). Further, until the time t1, since it is in the fixed speed change mode, the driving force is not assisted by the second motor generator MG2. Therefore, the output torque of second motor generator MG2 is zero until time t1. The rotation speed Nmg2 of the second motor generator MG2 is equal to the rotation speed of the drive shaft 3, and is kept constant while the shift mode is switched (see FIG. 6C).

  From time t1 to time t2, the engine torque of the engine 1 is controlled to decrease from the torque TKes to the engine torque TKec corresponding to the reaction force torque TKmg1 that can be output from the first motor generator MG1, and then the engine 1 Is controlled so as to gradually increase from the engine speed Nes (see FIG. 6A). Further, since the lock mechanism 7 is controlled so that the clutch plates of the clutch 7a slide, the first motor generator MG1 outputs the reaction torque TKmg1 to receive the engine torque of the engine 1 from time t1. . At this time, since a frictional force is generated between the clutch plates of the clutch 7a, the rotational speed of the first motor generator MG1 gradually increases from 0 (see FIG. 6B). Thereby, what is called a blow-up that the engine speed of the engine 1 rises rapidly can be prevented.

  Also, from time t1 to time t2, in order to keep the driving force constant, the output torque of the second motor generator is controlled to increase from 0 to TKmg2 as the engine torque of the engine 1 decreases. (See FIG. 6 (c)), driving force assist by the second motor generator MG2 is started. At this time, the electric power stored in advance in the HV battery 33 is supplied to the second motor generator MG2.

  After time t2, the lock mechanism 7 is controlled so that the clutch 7a is completely disengaged and enters the continuously variable transmission mode. At this time, the engine torque of the engine 1 is the torque TKec, and the engine speed of the engine 1 is Nec (see FIG. 6A). That is, in FIG. 3, the operating point reaches the point Pc2. First motor generator MG1 reaches a rotational speed Nmg1 defined by engine rotational speed Nec of engine 1 and rotational speed Nmg2 of drive shaft 3 (see FIG. 6B). The second motor generator MG2 outputs the torque TKmg2 and continues assisting the driving force. At this time, the electric power supplied to the second motor generator MG2 is generated in the first motor generator MG1. Is completely funded by the electricity.

  FIG. 6D shows a change in the ratio of each torque in the driving force with respect to time. As shown in FIG. 6D, since the second motor generator MG2 starts to output the torque TKmg2 to the drive shaft 3 from the time t1 to the time t2, the electric power stored in the HV battery 33 in advance becomes the second motor. It is supplied to the generator MG2. However, at this time, the first motor generator MG1 outputs the reaction force torque TKmg1, and the rotational speed also gradually increases. Therefore, the HV battery 33 is charged by the electric power generated in the first motor generator MG1. Therefore, with the passage of time, the power supplied to second motor generator MG2 is gradually covered by the power generated in first motor generator MG1. After time t2, first motor generator MG1 outputs reaction force torque TKmg1, and the rotation speed becomes rotation speed Nmg1, and the electric power supplied to the second motor generator is generated in first motor generator MG1. The amount of power stored completely in the HV battery 33 is hardly reduced by the generated power.

  Even using the method described above with reference to FIG. 6, the shift mode can be switched from the fixed shift mode to the continuously variable shift mode while maintaining the driving force constant, and a part of the output of the engine 1 can be changed to the second. Can be obtained as an output torque by the motor generator MG2. As a result, it is possible to smoothly output a desired driving force during high-speed traveling, thereby improving drivability.

  Next, switching from the continuously variable transmission mode to the fixed transmission mode will be described using an example in which the operating point in FIG. 3 is moved from the point Pc2 to the point Ps2. Hereinafter, it demonstrates concretely using FIGS. 7-8.

  FIG. 7 and FIG. 8 show examples of changes in operation of the engine and the motor generator with respect to time when switching from the continuously variable transmission mode to the fixed transmission mode, respectively. Specifically, referring to FIG. 4 described above, an example in which the collinear diagram changes from the straight line Ac1 to the straight line As1 is shown.

  First, the operation of the engine and motor generator shown in FIG. 7 will be described. In the example shown in FIG. 7, when switching from the continuously variable transmission mode to the fixed transmission mode, the operating point of the engine 1 is changed from the point Pc2 to the point Ps2 along the equal power line Lp2.

  FIG. 7A shows changes of the torque of the engine 1 (engine torque) and the rotational speed (engine rotational speed) with respect to time. FIG. 7B shows changes of the output torque and the rotational speed of the first motor generator MG1 with respect to time. FIG. 7C shows changes in the output torque and rotation speed of the second motor generator MG2 with respect to time. 7 (a) to 7 (c), the alternate long and short dash line indicates the change in torque over time, and the solid line indicates the change in rotation speed over time.

  Until the time t1, the continuously variable transmission mode, that is, the clutch 7a is released in the lock mechanism 7. At this time, the engine torque and the rotational speed of the engine 1 are the torque and the rotational speed corresponding to the operating point Pc2 in FIG. That is, the engine torque of the engine 1 is the engine torque TKec, and the engine rotation speed of the engine 1 is the rotation speed Nec (see FIG. 7A). The first motor generator MG1 outputs a reaction force torque TKmg1 corresponding to the engine torque TKec, and the rotation speed is the rotation speed Nmg1 (see FIG. 7B). Until time t1, second motor generator MG2 assists drive shaft 3 by outputting torque TKmg2. At this time, the electric power supplied to the second motor generator is completely covered by the electric power generated in the first motor generator MG1. The rotation speed Nmg2 of the second motor generator MG2 is equal to the rotation speed of the drive shaft 3, and is kept constant while the shift mode is switched (see FIG. 7C).

  From time t1 to time t2, the engine torque of the engine 1 is controlled to gradually increase from the torque TKec, and the engine speed of the engine 1 is controlled to gradually decrease from the rotation speed Nec (FIG. 7 (a )reference). Specifically, in FIG. 3, the operating point is controlled to move from the point Pc2 to the point Ps2 along the equal power line Lp2.

  Further, from time t1 to time t2, the lock mechanism 7 is controlled so that the clutch plates of the clutch 7a slide, that is, the state of the clutch 7a is close to a so-called half-clutch. Accordingly, a frictional force is generated between the clutch plates in the clutch 7a. From time t1 to time t2, since the hydraulic pressure of the actuator 7b in the clutch 7a is controlled to gradually increase, the frictional force between the clutch plates in the clutch 7a gradually increases. Therefore, from time t1 to time t2, the rotational speed of first motor generator MG1 gradually decreases from Nmg1 (see FIG. 7B).

  Further, from time t1 to time t2, the output torque of the second motor generator gradually decreases from TKmg2 as the output of the first motor generator MG1 decreases and the power generation amount also decreases (FIG. 7 ( c)). Here, the engine torque of the engine 1 gradually increases from the torque TKec, and the output torque of the second motor generator gradually decreases from the torque TKmg2, so that the driving force as a whole is kept constant.

  At time t2, the engine speed of the engine 1 becomes the rotation speed Nes (see FIG. 7A), so that the rotation speed of the first motor generator MG1 is zero as shown in the collinear diagram of FIG. Approach (see FIG. 4). Therefore, at this time, it is possible to completely engage the clutch 7a in the lock mechanism 7, that is, to switch to the fixed transmission mode without generating a shock. That is, by reducing the engine speed of the engine 1 to the rotational speed Ne, the rotational speed of the first motor generator MG1 can be brought close to 0, and it is possible to switch to the fixed speed change mode. When the clutch 7a in the lock mechanism 7 is completely engaged, the shift mode becomes the fixed shift mode, and the output torque of the first motor generator MG1 becomes 0 (see FIG. 7B).

  Further, at time t2, the engine torque of the engine 1 reaches the torque TKes (see FIG. 7A). Therefore, at this time, referring to FIG. 3, the operating point reaches the point Ps2. In the present embodiment, in the fixed speed change mode, the driving force is not assisted by the second motor generator MG2, so that the output torque of the second motor generator MG2 becomes 0 after time t2 (FIG. 7C). reference).

  FIG. 7D shows the change of the ratio of each torque in the driving force with respect to time. As shown in FIG. 7D, until the time t1, the second motor generator MG2 outputs torque by the electric power generated in the first motor generator MG1. From time t1 to t2, control is performed so that the torque of second motor generator MG2 gradually decreases. Further, from time t1 to t2, control is performed such that the engagement force of the clutch 7a in the lock mechanism 7 gradually increases and the engine torque of the engine 1 gradually increases. Therefore, from time t1 to t2, the ratio of the torque directly transmitted from the engine 1, that is, the ratio of the torque that is directly transmitted to the drive shaft 3 via the power distribution mechanism 20 out of the engine torque of the engine 1. To rise. At time t2, the speed change mode is completely switched to the fixed speed change mode, so that the driving force is covered by the torque directly transmitted from the engine 1.

  By using the method described above with reference to FIG. 7, the shift mode can be switched from the continuously variable transmission mode to the fixed transmission mode while keeping the driving force constant, and the fuel efficiency can be improved.

  Next, operations of the engine and motor generator shown in FIG. 8 will be described. In the example shown in FIG. 8, when switching from the continuously variable transmission mode to the fixed transmission mode, the magnitude of the engine torque of the engine 1 is set to the engine torque corresponding to the reaction force torque that can be output from the first motor generator MG1. While maintaining the magnitude, the engine speed of the engine 1 is reduced to a speed that can be switched to the fixed speed change mode, and then the speed change mode is changed to increase the engine torque of the engine 1.

  FIG. 8A shows changes in the torque of the engine 1 (engine torque) and the rotational speed (engine rotational speed) with respect to time. FIG. 8B shows changes in the output torque and rotation speed of the first motor generator MG1 with respect to time. FIG. 8C shows changes in the output torque and rotation speed of the second motor generator MG2 with respect to time. 8 (a) to 8 (c), the alternate long and short dash line indicates the change in torque over time, and the solid line indicates the change in rotation speed over time.

  Until the time t1, the continuously variable transmission mode, that is, the clutch 7a is released in the lock mechanism 7. At this time, the engine torque and the rotational speed of the engine 1 are the torque TKec and the rotational speed Nec corresponding to the operating point Pc2 in FIG. 3 (see FIG. 8A). The first motor generator MG1 outputs a reaction force torque TKmg1 corresponding to the engine torque TKec, and the rotation speed is the rotation speed Nmg1 (see FIG. 8B). Until time t1, second motor generator MG2 assists drive shaft 3 by outputting torque TKmg2. At this time, the electric power supplied to the second motor generator is completely covered by the electric power generated in the first motor generator MG1. The rotation speed Nmg2 of the second motor generator MG2 is equal to the rotation speed of the drive shaft 3, and is kept constant while the shift mode is switched (see FIG. 8C).

  From time t1 to time t2, the engine torque of the engine 1 is maintained at the torque TKec, and the engine speed of the engine 1 is controlled to gradually decrease from the speed Nec (see FIG. 8A). At this time, the lock mechanism 7 is controlled so that the clutch plates of the clutch 7a are not slid and the clutch plates of the clutch 7a are slipped. Accordingly, a frictional force is generated between the clutch plates in the clutch 7a. From time t1 to time t2, since the hydraulic pressure of the actuator in the clutch 7a is controlled to gradually increase, the frictional force between the clutch plates in the clutch 7a gradually increases. Therefore, from time t1 to time t2, the rotation speed of first motor generator MG1 gradually decreases from Nmg1 (see FIG. 8B).

  Further, from time t1 to time t2, in order to keep the driving force constant, the output torque of the second motor generator is held at TKmg2 (see FIG. 8C). At this time, since the output of the first motor generator MG1 decreases and the amount of power generation decreases, the electric power accumulated in the HV battery 33 is supplied to the second motor generator MG2.

  At time t2, the engine speed of the engine 1 becomes the rotation speed Nes (see FIG. 8A), so that the rotation speed of the first motor generator MG1 is 0 as shown in the collinear diagram of FIG. (See FIG. 4). At this time, the clutch 7a in the lock mechanism 7 can be completely engaged without generating a shock. When the clutch 7a in the lock mechanism 7 is completely engaged, the output torque of the first motor generator MG1 becomes 0 (see FIG. 8B). After the clutch 7a in the lock mechanism 7 is completely engaged, the engine torque of the engine 1 is controlled to be higher than the torque TKec and become the torque TKes. At this time, referring to FIG. 3, the operating point reaches the point Ps2. In the present embodiment, in the fixed speed change mode, the driving force is not assisted by the second motor generator MG2, so that the output torque of the second motor generator MG2 is controlled to 0 after time t2.

  FIG. 8D shows the change of the ratio of each torque in the driving force with respect to time. As shown in FIG. 8D, until the time t1, the second motor generator MG2 outputs a constant torque (torque TKmg2) by the electric power generated in the first motor generator MG1, and from time t1 to t2. Is also held constant. However, since the output of the first motor generator MG1 decreases and the amount of power generation decreases, the electric power stored in advance in the HV battery 33 is supplied to the second motor generator MG2. Since the power generation amount of the first motor generator MG1 gradually decreases, the ratio of the power stored in advance in the HV battery 33 gradually increases as the power supplied to the second motor generator MG2. At time t2, the speed change mode is completely switched to the fixed speed change mode, so that the driving force is covered by the torque directly transmitted from the engine 1.

  Even using the method described above with reference to FIG. 8, the shift mode can be switched from the continuously variable transmission mode to the fixed transmission mode while maintaining the driving force constant, and the fuel efficiency can be improved.

[Modification]
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.

  In addition, the hybrid vehicle mechanism to which the present invention can be applied is not limited to the one that realizes the fixed speed change mode by locking the rotor of the first motor generator MG1. Instead, for example, as shown in FIG. 9 below, the present invention can be applied to a mechanism that realizes the fixed speed change mode by fixing any one of the rotating elements of the power distribution mechanism 20 with a brake. It is possible to apply.

  FIG. 9 is a skeleton diagram showing a schematic configuration of a hybrid vehicle according to a modification. 9, 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 the fixed speed change mode is realized.

  The present invention can also be applied to a hybrid vehicle according to a modification. That is, when the engine torque corresponding to the reaction torque that exceeds the upper limit of torque that can be output by the first motor generator is output from the engine 1, the shift mode is switched from the continuously variable transmission mode to the fixed transmission mode. By doing so, it is not necessary to increase the size of the first motor generator MG1, and fuel consumption 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 device of the present invention can be applied to any hybrid vehicle having a fixed speed change mode in which the rotation speed ratio is fixed without outputting reaction force torque from the motor generator.

It is a figure showing the schematic structure of the hybrid vehicle concerning this embodiment. It is a figure which shows an example of the alignment chart in continuously variable transmission mode and fixed transmission mode. It is a figure which shows the operating point of an engine. It is a figure which shows an example of the alignment chart in continuously variable transmission mode and fixed transmission mode. It is a graph which shows an example of the operation | movement change with respect to the time of an engine and a motor generator when the transmission mode is switched from fixed transmission mode to continuously variable transmission mode. It is a graph which shows an example of the operation | movement change with respect to the time of an engine and a motor generator when the transmission mode is switched from fixed transmission mode to continuously variable transmission mode. It is a graph which shows an example of the operation | movement change with respect to the time of an engine and a motor generator when the transmission mode is switched from continuously variable transmission mode to fixed transmission mode. It is a graph which shows an example of the operation | movement change with respect to the time of an engine and a motor generator when the transmission mode is switched from continuously variable transmission mode to fixed transmission mode. It is a figure which shows schematic structure of the hybrid vehicle which concerns on a modification.

Explanation of symbols

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

Claims (3)

An engine, a motor generator, a power distribution mechanism to which the engine and the motor generator are coupled, and a drive shaft to which an output from the power distribution mechanism is transmitted. In response to the above, the motor generator outputs a reaction force torque, and continuously changes the rotation speed ratio between the engine rotation speed of the engine and the rotation speed of the drive shaft; A control device for a hybrid vehicle applied to a hybrid vehicle having a fixed speed change mode for fixing the rotational speed ratio without outputting force torque,
When the reaction torque corresponding to the engine torque exceeds the upper limit of torque that can be output by the motor generator, a control means for switching the shift mode from a continuously variable transmission mode to a fixed transmission mode ,
The hybrid vehicle includes an assist motor generator that outputs torque to the drive shaft by electric power generated by the motor generator in a continuously variable transmission mode.
The control means includes
When the shift mode is set to the fixed shift mode, if it is determined that there is an acceleration request, the engine torque is increased,
When there is a driving force request exceeding the maximum engine torque of the engine, the magnitude of the engine torque output from the engine is reduced to the magnitude of the engine torque corresponding to the reaction force torque that can be output from the motor generator. After that, the engine speed is increased, and torque is output from the assist motor generator to the drive shaft, thereby switching the shift mode from the fixed shift mode to the continuously variable shift mode. Control device. The hybrid vehicle includes a lock mechanism capable of fixing a rotor of the motor generator,
The control means fixes the rotor of the motor generator when switching from the continuously variable transmission mode to the fixed transmission mode, and releases the rotor of the motor generator when switching from the fixed transmission mode to the continuously variable transmission mode. The hybrid vehicle control device according to claim 1. The engine control apparatus for a hybrid vehicle according to claim 1 or 2 is a diesel engine.

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