JP2010284997A - Control device for hybrid car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the control device of a hybrid car for improving fuel consumption. <P>SOLUTION: The control device of a hybrid car is applied to a hybrid car having an engine, a motor generator, a power distribution mechanism, and a lock mechanism which is connected to any rotating element in the power distribution mechanism and in which a rotating element can be fixed according as an engagement in which engagement elements are engaged with each other. The control device of the hybrid car includes a switching control means, a driving force characteristics setting means, and a driving force control means. The driving force characteristics setting means makes the rate of the change of the driving force with respect to an accelerator aperture when a fixed shift transmission mode smaller than the rate of the change of the driving force with respect to an accelerator aperture for a variable speed mode. The driving force control means changes the driving force during the switching of the shift transmission mode in response to the changing speed of the accelerator aperture in switching of the shift transmission mode from the fixed shift transmission mode to the variable speed mode. <P>COPYRIGHT: (C)2011,JPO&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, as shown in Patent Document 1 below, a continuously variable transmission mode capable of continuously changing the rotational speed ratio between the power source and the output member, and the rotational speed There is a hybrid vehicle that can switch between a fixed transmission mode and a fixed ratio.

JP 2004-345527 A

  By the way, in the hybrid vehicle described in Patent Document 1, the rate of change in driving force with respect to the accelerator opening is the same in the continuously variable transmission mode and the fixed transmission mode. Therefore, in the fixed speed change mode, the adjustment of the driving force can hardly be performed, the engine operating point is uniquely determined by the vehicle speed, and the fuel efficiency may be deteriorated due to the restriction of the engine operating point.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a hybrid vehicle control device capable of improving fuel consumption.

  In one aspect of the present invention, an engine, a motor generator, a power distribution mechanism connected to the engine and the motor generator, a drive shaft to which an output from the power distribution mechanism is transmitted, and the power distribution mechanism A hybrid vehicle control device applied to a hybrid vehicle having a lock mechanism that is coupled to any of the rotation elements and that can fix the rotation elements by engaging the engagement elements corresponds to the engine torque of the engine. A speed change mode between a continuously variable transmission mode in which the reaction force torque is output to the motor generator and a fixed transmission mode in which the rotation element is fixed by the lock mechanism and the reaction force torque is received by the lock mechanism. Switching control means for switching between, and the change of the driving force with respect to the accelerator opening in the continuously variable transmission mode. Driving force characteristic setting means for reducing the rate of change of the driving force with respect to the accelerator opening in the case of the fixed speed change mode, and when switching the speed change mode from the fixed speed change mode to the continuously variable speed change mode. Driving force control means for changing the driving force during the shift mode switching in accordance with the changing speed of the accelerator opening.

  The hybrid vehicle control apparatus includes an engine, a motor generator, a power distribution mechanism connected to the engine and the motor generator, a drive shaft to which an output from the power distribution mechanism is transmitted, and any of the power distribution mechanisms. The present invention is applied to a hybrid vehicle that includes a lock mechanism that is coupled to a rotating element and that can fix the rotating element by engaging the engaging elements. The hybrid vehicle control device is realized by, for example, an ECU (Electronic Control Unit), and includes a switching control unit, a driving force characteristic setting unit, and a driving force control unit. The switching control means includes a continuously variable transmission mode in which a reaction force torque corresponding to the engine torque of the engine is output to the motor generator, and a fixed transmission mode in which the rotation element is fixed by the lock mechanism and the reaction force torque is received by the lock mechanism. Change the shift mode between and. The driving force characteristic setting means makes the rate of change of the driving force with respect to the accelerator opening in the case of the fixed shift mode smaller than the rate of change of the driving force with respect to the accelerator opening in the case of the continuously variable transmission mode. The driving force control means changes the driving force during the shift mode switching according to the changing speed of the accelerator opening when the shift mode is switched from the fixed shift mode to the continuously variable shift mode. By doing so, fuel efficiency can be improved and drivability during the shift mode switching can be improved.

  In a preferred embodiment of the above-described hybrid vehicle control device, the driving force control means increases the change rate of the accelerator opening when the shift mode is switched from the fixed shift mode to the continuously variable transmission mode. As the change rate of the driving force during the shift mode switching is increased and the change rate of the accelerator opening is decreased, the change rate of the drive force during the shift mode switching is decreased. In this way, it is possible to suppress a driving force step when switching the transmission mode. In addition, according to this, when the driver wants to produce the desired driving force quickly after the shift mode switching, the change in the driving force can be accelerated, and the target driving force after the shift mode switching can be quickly reached. it can.

  In another aspect of the hybrid vehicle control device, the driving force control means may be configured such that the accelerator opening is constant when the shift mode is switched from the fixed shift mode to the continuously variable shift mode. First, the change speed of the driving force during the shift mode switching is made smaller than when the accelerator opening changes. As a result, when the accelerator opening is constant, even if the shift mode is switched from the fixed shift mode to the continuously variable shift mode due to, for example, a battery charging request, the step of the driving force is reduced. Can be suppressed.

  In a preferred embodiment of the control apparatus for a hybrid vehicle, the lock mechanism is coupled to a rotor of the motor generator, and the switching control means is configured to perform a fixed speed change by fixing the rotor of the motor generator by the lock mechanism. Realize the mode.

  An engine, a motor generator, a power distribution mechanism to which the engine and the motor generator are connected, a drive shaft to which an output from the power distribution mechanism is transmitted, and any rotation element in the power distribution mechanism. A control device for a hybrid vehicle applied to a hybrid vehicle having a lock mechanism capable of fixing the rotating element by engagement of the engaging elements, the reaction force torque corresponding to the engine torque of the engine being the motor generator Switching control means for switching the transmission mode between a continuously variable transmission mode to be output to the fixed transmission mode and the fixed transmission mode in which the rotating element is fixed by the locking mechanism and the reaction force torque is received by the locking mechanism; More than the rate of change in driving force with respect to accelerator opening in the case of continuously variable transmission mode, The driving force characteristic setting means for reducing the rate of change of the driving force with respect to the accelerator opening in the speed mode, and the change rate of the accelerator opening when the shift mode is switched from the fixed transmission mode to the continuously variable transmission mode. And a driving force control means for changing the driving force during the shift mode switching. By doing so, fuel efficiency can be improved and drivability during the shift mode switching can be improved.

1 is a schematic configuration of a hybrid vehicle to which a control device according to the present embodiment is applied. An example of an alignment chart in a continuously variable transmission mode and a fixed transmission mode is shown. It is a drive force diagram in the control method of a general hybrid vehicle. It is a drive force diagram in the control method of the hybrid vehicle concerning this embodiment. It is a graph which shows the change with respect to the time of the accelerator opening degree at the time of transmission mode switching, and a driving force.

  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 a control device according to this embodiment 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 reduction gear 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. The first motor generator MG1 functions as a motor generator in the present invention.

  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. The clutch 7a has a pair of engaging elements that engage with each other. Of the pair of engagement elements, one engagement element is fixed to a case or the like, and the other engagement element is coupled to the rotor 11 of the first motor generator MG1. The lock mechanism 7 is configured to be able to engage and release the engagement elements in the clutch 7a using the actuator 7b. Specifically, the actuator 7b engages the clutch 7a by, for example, a hydraulic pressure. 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. That is, the clutch 7a functions as a brake that fixes the sun gear S1 of the power distribution mechanism 20. The lock mechanism 7 controls the engagement / release of the clutch 7a by controlling the actuator 7b based on the control signal Sig5 transmitted from the ECU 4.

  In a state where the lock mechanism 7 releases the clutch 7a, the sun gear S1 is released, and the engine speed of the engine 1 continuously changes by continuously changing the speed of the first motor generator MG1. A step shift mode is realized. On the other hand, when the lock mechanism 7 is engaged with the clutch 7a, the sun gear S1 is fixed and the gear ratio determined by the power distribution mechanism 20 is in the overdrive state (that is, the engine speed of the engine 1 is the drive shaft 3). In this state, a fixed speed change mode is realized that is fixed to a state where the rotational speed is smaller than the number of revolutions.

  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 based on the detection signal from the accelerator opening sensor 23 and detects the vehicle speed based on the detection signal from the vehicle speed sensor 22. The ECU 4 calculates the driving force based on the detected accelerator opening and the vehicle speed, and controls the engine 1, the first motor generator MG1, and the second motor generator MG2 so as to obtain the calculated driving force. . Further, the ECU 4 controls the lock mechanism 7 based on the detected vehicle speed and the calculated driving force.

  Next, 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, the upward direction corresponds to the positive rotation, and the downward direction corresponds to the negative rotation. In FIGS. 2A and 2B, the upward torque corresponds to the positive torque, and the downward torque corresponds to the 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. Here, as can be seen from FIG. 2A, the engine torque TKE is a positive torque and the torque TK1 is a negative torque. 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, the clutch 7 a of the lock mechanism 7 is responsible for the reaction torque corresponding to the engine torque of the engine 1. Since first motor generator MG1 does not function as either a generator or an electric motor, power is not supplied from first motor generator MG1 to second 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.

[Control method]
Next, a method for controlling the hybrid vehicle according to the present embodiment will be specifically described.

  FIG. 3 shows a driving force diagram in a general hybrid vehicle control method, where the vertical axis shows the driving force and the horizontal axis shows the vehicle speed. FIG. 3 shows driving force lines when the accelerator opening is 20%, 40%, 60%, 80%, and 100%. The ECU 4 calculates the driving force using the relationship shown in FIG. 3 based on the accelerator opening and the vehicle speed, and controls the engine 1 and the motor generator so as to obtain the calculated driving force. For example, when the vehicle speed is Vex and the accelerator opening is 40%, the driving force is calculated as Tex.

  In FIG. 3, a hatched area SA indicates a lock area set in the fixed speed change mode. The lock area SA is set according to the vehicle speed and the driving force. Moreover, in FIG. 3, an example of the operating point (vehicle operating point) of the vehicle defined by the vehicle speed and the driving force is indicated by white circles. When the vehicle operating point is located in the lock area SA, the ECU 4 engages the clutch 7a of the lock mechanism 7 and sets the shift mode to the fixed shift mode. On the other hand, when the vehicle operating point is located outside the lock area SA, the ECU 4 releases the clutch 7a of the lock mechanism 7 and sets the shift mode to the continuously variable transmission mode.

  In a general hybrid vehicle control method, when the driver depresses the accelerator, the accelerator opening increases, and the driving force also increases in proportion to the accelerator opening. For example, as indicated by an arrow W1, when the driver depresses the accelerator at a predetermined vehicle speed Va and the accelerator opening increases and exceeds 20%, the vehicle moves from outside the lock area SA into the lock area SA. The point moves. At this time, the ECU 4 switches the transmission mode from the continuously variable transmission mode to the fixed transmission mode. Then, as shown by arrow W2, when the accelerator opening further increases and exceeds 40%, the vehicle operating point moves from the lock area SA to the outside of the lock area SA. At this time, the ECU 4 releases the clutch 7a of the lock mechanism 7 and switches the transmission mode from the fixed transmission mode to the continuously variable transmission mode. After the accelerator opening exceeds 40%, even if the accelerator opening further increases, the ECU 4 keeps the shift mode in the continuously variable transmission mode.

  As can be seen from the above, the shift mode is set to the fixed shift mode when the accelerator opening is in a relatively short range between 20% and 40%. In other words, in the example shown in FIG. 3, the rate of change of the driving force with respect to the accelerator opening is relatively large for the driving force range Tsa in which the shifting mode is set to the fixed shifting mode. This is because the rate of change of the driving force with respect to the accelerator opening is set to be the same in both the continuously variable transmission mode and the fixed transmission mode. For this reason, when the shift mode is set to the fixed shift mode, it is difficult for the driver to adjust the driving force by adjusting the accelerator opening, and the driving force is uniquely determined.

  When the speed change mode is set to the fixed speed change mode, the engine speed is determined when the vehicle speed proportional to the speed of the drive shaft 3 is determined, and the engine torque is determined when the driving force is determined. In the example shown in FIG. 3, since the driving force is uniquely determined when the transmission mode is set to the fixed transmission mode, the engine operating point defined by the engine torque and the engine speed is also uniquely determined according to the vehicle speed. Determined. Here, on the map defined by the engine torque and the engine speed, the engine operating point is restricted from the viewpoint of noise prevention and exhaust emission. In other words, even when the vehicle operating point moves into the lock area SA and the shift mode is set to the fixed shift mode, the ECU 4 may change the lock mechanism 7 depending on the position of the engine operating point determined at that time. It is necessary to release the clutch 7a and switch the transmission mode to the continuously variable transmission mode. In such a case, even when the vehicle operating point is located in the lock region SA, the shift mode is switched from the fixed shift mode to the continuously variable shift mode, so that fuel consumption may be deteriorated.

  In addition, when the driver performs rough accelerator operation, the vehicle operating point immediately deviates from the lock area SA and shifts from the fixed transmission mode to the continuously variable transmission mode, even though the driver does not intend to produce driving force. The mode may change. In such a case, even if the driver does not intend to give driving force, fuel efficiency is deteriorated.

  Therefore, in the hybrid vehicle control method according to the present embodiment, the ECU 4 varies the driving force characteristics in each of the continuously variable transmission mode and the fixed transmission mode. Specifically, the ECU 4 makes the rate of change of the driving force with respect to the accelerator opening in the case of the fixed speed change mode smaller than the rate of change of the driving force with respect to the accelerator opening in the case of the continuously variable transmission mode. . This will be specifically described below.

  FIG. 4 is a driving force diagram in the hybrid vehicle control method according to the present embodiment, in which the vertical axis indicates the driving force and the horizontal axis indicates the vehicle speed. FIG. 4 shows the accelerator opening in the case of the continuously variable transmission mode and the accelerator opening in the case of the fixed transmission mode.

  In the example shown in FIG. 3, when the driver depresses the accelerator and the accelerator opening exceeds 20%, the ECU 4 switches the shift mode from the continuously variable transmission mode to the fixed transmission mode. The rate of change in the driving force with respect to is constant in the fixed speed change mode and in the continuously variable speed mode. Therefore, when the shift mode is set to the fixed shift mode, the ECU 4 increases the drive force by the range Tsa of the drive force in the fixed shift mode when the accelerator opening is changed from 20% to 40%. It was changing.

  On the other hand, in the hybrid vehicle control method according to the present embodiment, the ECU 4 controls the driving force with respect to the accelerator opening in the fixed shift mode rather than the rate of change in the driving force with respect to the accelerator opening in the continuously variable transmission mode. The rate of change is reduced. For example, in the example shown in FIG. 4, the ECU 4 sets the accelerator opening range for setting the shift mode to the fixed shift mode between 20% and 80%. More specifically, the ECU 4 changes the accelerator opening from 20% to 40%, from 40% to 60%, and from 60% to 80% when the transmission mode is switched from the continuously variable transmission mode to the fixed transmission mode. In each case, the driving force is changed by a range Tsam smaller than the range Tsa. That is, when the accelerator opening changes from 20% to 80%, the ECU 4 changes the driving force by the driving force range Tsa in the fixed speed change mode. When the accelerator opening exceeds 80%, the ECU 4 switches the transmission mode from the fixed transmission mode to the continuously variable transmission mode.

  As described above, in the case of the fixed speed change mode, the driver can adjust the driving force by adjusting the accelerator opening by reducing the rate of change of the driving force with respect to the accelerator opening. As a result, the engine operating point can be arbitrarily set in the case of the fixed speed change mode. Therefore, when the vehicle operating point is located in the lock region SA, it is possible to enter the continuously variable transmission mode due to the restriction of the engine operating point. There is no need to perform switching, and fuel consumption can be improved. In the case of the fixed speed change mode, the ratio of change in the driving force with respect to the accelerator opening is reduced, so that even when the driver performs a rough accelerator operation, it is possible to immediately switch to the continuously variable speed change mode. The fuel consumption can be improved.

  Here, in the case of the fixed speed change mode, the accelerator opening is changed from 20% to 80% in order to change the driving force by the range Tsa, but the present invention is not limited to this. That is, it goes without saying that the maximum value of the accelerator opening in the case of the fixed speed change mode is not limited to 80%.

  For example, the accelerator opening may be changed from 20% to 60% in order to change the driving force by the range Tsa by setting the maximum value of the accelerator opening in the fixed shift mode to 60%. In this case, as compared with the above-described example in which the maximum value of the accelerator opening in the fixed shift mode is set to 80%, the rate of change of the driving force with respect to the accelerator opening in the fixed shift mode is increased. Further, for example, in order to change the driving force by the range Tsa by setting the maximum value of the accelerator opening in the fixed shift mode to 90%, the accelerator opening may be changed from 20% to 90%. In this case, as compared with the above-described example in which the maximum value of the accelerator opening in the fixed shift mode is 80%, the rate of change of the driving force with respect to the accelerator opening in the fixed shift mode is small.

  However, the maximum value of the accelerator opening in the case of the fixed speed change mode is preferably smaller than 100%. Accordingly, when the driver depresses the accelerator and the accelerator opening exceeds the maximum value, the shift mode can be switched from the fixed shift mode to the continuously variable shift mode.

[Transmission mode switching control method]
Next, the shift mode switching control method according to this embodiment will be described. In the example shown in FIG. 4, when the shift mode is switched from the fixed shift mode to the continuously variable shift mode, a step in the driving force is generated. This will be specifically described below.

  In the example shown in FIG. 4, the ECU 4 changes the driving force by the range Tsa when the accelerator opening changes from 20% to 80% in the fixed speed change mode. Then, when the accelerator opening exceeds 80%, the ECU 4 switches the transmission mode from the fixed transmission mode to the continuously variable transmission mode. However, here, the driving force when the accelerator opening exceeds 80% in the case of the fixed shift mode and the driving force when the accelerator opening exceeds 80% in the case of the continuously variable transmission mode are greatly different. . For example, as shown in FIG. 4, in the case where the vehicle speed is Va, when the shift mode is switched from the fixed shift mode to the continuously variable shift mode when the accelerator opening exceeds 80%, the vehicle operation The point moves from the point Psa to the point Pca. Along with this, the driving force also rapidly increases from the driving force Tsh in the fixed shift mode to the driving force Tch in the continuously variable transmission mode. As described above, when the change rate of the driving force with respect to the accelerator opening is changed for each shift mode, when the shift mode is switched from the fixed shift mode to the continuously variable transmission mode, A step will occur, and the driver may feel uncomfortable.

  Therefore, in the shift mode switching control method according to the present embodiment, when the shift mode is switched from the fixed shift mode to the continuously variable shift mode, the ECU 4 drives during the shift mode switching according to the changing speed of the accelerator opening. Let's change the force. This will be specifically described below with reference to FIG.

  FIG. 5 is a graph showing changes in the accelerator opening and the driving force with respect to time when the transmission mode is switched from the fixed transmission mode to the continuously variable transmission mode. The graph 201a shows the change of the accelerator opening with respect to time when the change of the accelerator opening is slow, and the graph 201b shows the change of the accelerator opening with respect to time when the change of the accelerator opening is relatively fast. That is, the graph 201a shows a graph when the change rate of the accelerator opening is small, and the graph 201b shows a graph when the change rate of the accelerator opening is high. Further, the graph 202a shows the change with respect to time of the driving force when the change in the accelerator opening becomes the graph 201a, and the graph 202b shows the change with time of the driving force when the change in the accelerator opening becomes the graph 201b. Show.

  In the case of the fixed shift mode, when the accelerator opening increases and the accelerator opening exceeds a threshold value Acp (80% in the example shown in FIG. 4), the ECU 4 switches from the fixed shift mode to the continuously variable shift mode. And change the shifting mode.

  At this time, the ECU 4 obtains the change rate of the accelerator opening based on the detection signal from the accelerator opening sensor 23. Then, as shown in the graph 201a, when the change rate of the accelerator opening is small, the ECU 4 slows down the change of the driving force, that is, reduces the change rate of the driving force, as shown in the graph 202a. Thereby, it is possible to suppress a step in the driving force when the transmission mode is switched from the fixed transmission mode to the continuously variable transmission mode. On the other hand, as shown in the graph 201b, when the change rate of the accelerator opening is large, the ECU 4 determines that the driver wants to give the desired driving force early after the shift mode is changed, and the driving force Is increased, that is, the change speed of the driving force is increased.

  As described above, in the shift mode switching control method for the hybrid vehicle according to the present embodiment, the ECU 4 shifts according to the changing speed of the accelerator opening when the shift mode is switched from the fixed shift mode to the continuously variable shift mode. The driving force during mode switching is changed. Specifically, the ECU 4 increases the change rate of the driving force during the shift mode switching as the change rate of the accelerator opening increases, and the ECU 4 decreases the drive force during the change of the shift mode as the change rate of the accelerator opening decreases. Reduce the rate of change. In this way, it is possible to suppress a driving force step when switching the transmission mode. Further, according to this, when the driver wants to obtain a desired driving force early after the shift mode switching, the change in the driving force can be accelerated, and the target driving force after the shift mode switching can be quickly obtained. Can reach.

  Even when the vehicle operating point is located in the lock region SA and the accelerator opening is constant, the fixed shift mode is changed to the continuously variable shift mode, for example, due to the charging request of the HV battery 33 or the like. And the shift mode may be switched. At this time, although the accelerator opening is not changed, a step in the driving force is generated, and the driver may feel uncomfortable.

  Therefore, in such a case, the ECU 4 may delay the change in the driving force during the shift mode switching compared to the case where the accelerator opening changes, that is, the change in the driving force during the shift mode switching. The speed may be reduced. As a result, when the accelerator opening is constant, even if the shift mode is switched from the fixed shift mode to the continuously variable shift mode due to, for example, a charge request for the HV battery 33, the driving force A step can be suppressed.

  As can be seen from the above description, in the shift mode switching control method for the hybrid vehicle according to the present embodiment, the ECU 4 changes the accelerator opening when switching the shift mode from the fixed shift mode to the continuously variable shift mode. The driving force during the shift mode switching is changed according to the speed. In this way, drivability during the shift mode switching can be improved.

[Modification]
In addition, this invention is not limited to said each form, In the range of the summary of this invention, it can implement with a various form. For example, the hybrid vehicle mechanism to which the present invention can be applied is not limited to a mechanism having a mechanism for realizing the fixed speed change mode by locking the rotor of the first motor generator MG1. Instead, for example, the present invention can be applied even to a mechanism that realizes the fixed transmission mode by locking any one of the rotating elements of the power distribution mechanism with a brake. . For example, in addition to the power distribution mechanism 20 described above, a new power distribution mechanism connected to the power distribution mechanism 20 is provided, and any one rotating element of the new power distribution mechanism is locked by a brake. The present invention can also be applied to a hybrid vehicle configured to be able to. In other words, in addition to the three points of the first motor generator MG1, the engine 1, and the drive shaft 3 shown in FIG. The present invention is applicable.

  Further, in addition to the above-described mechanisms, the present invention can be applied to a mechanism of a so-called multi-mode type hybrid vehicle further including a fixed transmission device having a plurality of shift stages.

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

Claims (4)

An engine, a motor generator, a power distribution mechanism to which the engine and the motor generator are connected, a drive shaft to which an output from the power distribution mechanism is transmitted, and any rotation element in the power distribution mechanism. A control device for a hybrid vehicle applied to a hybrid vehicle having a lock mechanism capable of fixing the rotating element by engagement between the engagement elements,
A continuously variable transmission mode in which a reaction force torque corresponding to the engine torque of the engine is output to the motor generator, and a fixed transmission in which the rotation element is fixed by the lock mechanism and the reaction force torque is received by the lock mechanism. Switching control means for switching a shift mode between modes,
Driving force characteristic setting means for reducing the rate of change in driving force with respect to the accelerator opening in the case of the fixed shift mode, rather than the rate of change in driving force with respect to the accelerator opening in the case of the continuously variable transmission mode;
Driving force control means for changing the driving force during switching of the shift mode according to the changing speed of the accelerator opening when the shift mode is switched from the fixed shift mode to the continuously variable transmission mode. A control device for a hybrid vehicle.   The drive force control means increases the change rate of the drive force during the shift mode switching as the change rate of the accelerator opening increases when the shift mode is switched from the fixed shift mode to the continuously variable transmission mode. The control apparatus for a hybrid vehicle according to claim 1, wherein the change speed of the driving force during the shift mode switching is reduced as the change speed of the accelerator opening is reduced.   When the accelerator opening is constant when the shift mode is switched from the fixed transmission mode to the continuously variable transmission mode, the driving force control means is compared with a case where the accelerator opening changes. 3. The control apparatus for a hybrid vehicle according to claim 1, wherein the change speed of the driving force during the shift mode switching is reduced. The lock mechanism is connected to a rotor of the motor generator,
4. The hybrid vehicle control device according to claim 1, wherein the switching control unit realizes a fixed speed change mode by fixing a rotor of the motor generator by the lock mechanism. 5.

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