JP5157871B2 - Control device for hybrid vehicle - Google Patents

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 the following Patent Documents 1 to 3, a continuously variable transmission mode capable of continuously converting the rotational speed of the generator and a fixed transmission mode in which the transmission gear ratio is fixed. There is a hybrid vehicle that is configured to be able to switch between and to drive. In the continuously variable transmission mode, the reaction torque corresponding to the engine torque is output to the motor generator, and the engine speed is continuously changed by continuously changing the engine speed. In the fixed transmission mode, the rotation of one rotating element in the planetary gear mechanism is prevented, and the transmission ratio is fixed.

  Here, when the shift mode is switched, the rotational speed of the engine or the motor generator changes greatly. For this reason, the following Patent Document 1 discloses a target rotational speed of a rotating element that accompanies shift mode switching between a continuously variable transmission mode region and a fixed transmission mode region on a map defined by a required driving force and a vehicle speed. A hybrid vehicle control device provided with a transition region for continuously setting changes is described.

  In Patent Document 2, either the continuously variable transmission mode or the fixed transmission mode is selectively switched to either the continuously variable transmission mode or the fixed transmission mode based on whether the fuel consumption rate is good in the continuously variable transmission mode or the fixed transmission mode. A control device for a vehicle drive device is described. Further, in Patent Document 3, in a hybrid vehicle having a configuration capable of switching between a non-generator mode in which a generator is stopped by a brake and a power generation mode in which a brake is released, the brake is applied after the generator rotational speed is brought close to zero. A technique for reducing the shock at the time of engagement by engaging is described.

JP 2005-163912 A JP-A-2005-240917 JP 2001-1773 A

  However, in the hybrid vehicle control device described in Patent Document 1, the operating point is changed with a constant inclination α in the transition region even in a region that is relatively far from the fixed shift mode region. For this reason, depending on the magnitude of the inclination α, the fuel efficiency may be deteriorated in the transition region.

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

  In one aspect of the present invention, the present invention is applied to a hybrid vehicle having a driving force source and configured to be capable of switching a transmission mode between a continuously variable transmission mode and a fixed transmission mode. A control apparatus for a hybrid vehicle comprising control means for switching a shift mode according to a position of a vehicle operating point on a map defined by an accelerator opening and a vehicle speed, in which a fixed shift mode region is set, On the map, a transition region is set adjacent to the fixed shift mode region to bring the rotation number of the driving force source close to the fixed shift mode rotation number that is the rotation number of the driving force source in the fixed shift mode. When the vehicle operating point is located in the transition region, the control means is configured to rotate the vehicle in the fixed shift mode as the vehicle operating point approaches the fixed shift mode region. The ratio closer the rotational speed of the driving power source for the number increased.

  The above hybrid vehicle control device is preferably applied to a hybrid vehicle having a driving force source and configured to be able to switch the speed change mode between the continuously variable speed mode and the fixed speed change mode. A control device for a hybrid vehicle is a control for switching a shift mode according to a position of a vehicle operating point on a map defined by an accelerator opening and a vehicle speed in which a continuously variable transmission mode region and a fixed transmission mode region are set. Means. On the map, a transition region in which the rotational speed of the driving force source is brought close to the rotational speed in the fixed transmission mode, which is the rotational speed of the driving force source in the fixed transmission mode, is set adjacent to the fixed transmission mode region. When the vehicle operating point is located in the transition region, the control means increases the rate at which the rotational speed of the driving force source approaches the rotational speed in the fixed transmission mode as the vehicle operating point approaches the fixed transmission mode area. As a result, a decrease in drivability can be prevented and engine efficiency deterioration can be suppressed.

  According to another aspect of the hybrid vehicle control device, the hybrid vehicle includes an engine that is a driving force source, a motor generator, a power distribution mechanism that connects the engine and the motor generator, and the power distribution mechanism. A drive shaft to which an output from the power is transmitted, and an engagement mechanism that is connected to any rotation element in the power distribution mechanism and fixes or releases the rotation element, and the control means includes the engagement The speed change mode is switched between the fixed speed change mode and the continuously variable speed change mode by fixing or releasing the rotating element by a mechanism. Here, the fixed speed mode rotation speed is the engine rotation speed when the rotation speed of the rotating element connected to the engagement mechanism becomes zero. Thereby, the shock by engagement of an engagement mechanism can be prevented.

  According to another aspect of the hybrid vehicle control device, the control means may be configured to display a map defined by an engine speed and an engine torque when the engine speed is brought close to the engine speed in the fixed shift mode. The engine operating point is moved along the equal power line. As a result, the driving force can be kept constant.

  This is applied to a hybrid vehicle having a driving force source and configured to be able to switch between two speed modes, a continuously variable transmission mode and a fixed transmission mode, and a continuously variable transmission mode area and a fixed transmission mode area are set. A control device for a hybrid vehicle comprising control means for switching a shift mode according to the position of the vehicle operating point on a map defined by the accelerator opening and the vehicle speed, wherein the fixed shift mode is displayed on the map. A transition region is set adjacent to the fixed speed change mode region to make the rotation speed of the drive force source close to the rotation speed in the fixed speed change mode, which is the rotation speed of the driving force source at the time, and the control means Is located in the transition region, the closer the vehicle operating point is to the fixed transmission mode region, the more the driving force source for the rotational speed in the fixed transmission mode. The ratio closer the rotational speed is increased. As a result, a decrease in drivability can be prevented and engine efficiency deterioration can be suppressed.

  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 each 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 driving force 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 drive force source for assisting the torque (drive force) or the 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. Therefore, 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. Therefore, the second motor generator MG2 functions as an assist motor generator in the present invention.

  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. One engagement element is fixed to a case or the like, and the other engagement element is connected to the rotor 11 of the first motor generator MG1. The lock mechanism 7 is configured to be able to engage and release the clutch 7a using an 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 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. Further, the ECU 4 controls the lock mechanism 7 based on a vehicle speed detected based on a detection signal from a vehicle speed sensor (not shown) and an engine speed detected based on a detection signal from a crank angle sensor (not shown). To do. Therefore, the ECU 4 functions as a control unit in the present invention.

  Next, the operation state of the hybrid vehicle in the continuously variable transmission mode and the fixed transmission 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 the 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.

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

  FIG. 3 is a diagram showing how the vehicle operating point (vehicle operating point) moves on the map defined by the vehicle speed and the accelerator opening, where the vertical axis indicates the accelerator opening and the horizontal axis indicates the vehicle speed. ing. Vehicle operating points are indicated by white circles.

  On the map shown in FIG. 3, a fixed transmission mode area Ars and a continuously variable transmission mode area Arc are set. On the map, a transition area Arr is set in the continuously variable transmission mode area Arc adjacent to the fixed transmission mode area Ars.

  The ECU 4 holds, in a memory or the like, a map (shift mode determination map) showing the relationship between the vehicle speed, the accelerator opening, and the shift mode shown in FIG. The ECU 4 determines whether the vehicle operating point is located in the continuously variable transmission mode area Arc or the fixed transmission mode area Ars based on the transmission mode determination map. When the ECU 4 determines that the vehicle operating point is located in the fixed transmission mode area Ars, the ECU 4 switches the transmission mode to the fixed transmission mode. On the other hand, when the ECU 4 determines that the vehicle operating point is located in the continuously variable transmission mode area Arc, the ECU 4 switches the transmission mode to the continuously variable transmission mode. The map is defined by the vehicle speed and the accelerator opening, but is not limited to this, and may be defined by the vehicle speed and driving force instead.

  As indicated by the arrow W, when the vehicle operating point moves from the continuously variable transmission mode region Arc to the fixed transmission mode region Ars, the ECU 4 performs control to switch the transmission mode from the continuously variable transmission mode to the fixed transmission mode. When the switching control of the transmission mode from the continuously variable transmission mode to the fixed transmission mode is performed, the ECU 4 engages the clutch 7a after performing the rotational speed synchronization control of the engagement element of the clutch 7a. As the rotation speed synchronization control, the ECU 4 sets the rotation speed of the engagement element connected to the rotor 11 of the first motor generator MG1 to “0”. Specifically, the ECU 4 sets the rotation speed of the rotation element of the power distribution mechanism 20 connected to the engagement element, here, the rotation speed of the sun gear S1, that is, the rotation speed of the first motor generator MG1 to “0”. To. By doing so, it is possible to prevent the occurrence of a shock due to the engagement of the clutch 7a when the transmission mode is switched.

  First, a general shift mode switching control method will be described with reference to FIG. FIG. 4 shows how the nomograph changes during a general shift mode switching control.

  In FIG. 4, straight lines Ac <b> 1 and Ac <b> 2 are examples of collinear diagrams in the continuously variable transmission mode. Specifically, straight line Ac1 is a collinear diagram when first motor generator MG1 is rotating forward in the continuously variable transmission mode, and rotation speed N1 indicates the rotation speed of drive shaft 3 at that time. ing. A straight line Ac2 is a collinear diagram when the first motor generator MG1 is in a negative rotation in the continuously variable transmission mode, and a rotation speed N2 indicates the rotation speed of the drive shaft 3 at that time. The straight lines As1 and As2 are examples of collinear charts in the fixed speed change mode.

  First, the case where first motor generator MG1 is rotating forward in the continuously variable transmission mode will be described. In this case, when the ECU 4 determines that the vehicle operating point has moved to the fixed speed change mode region Ars, the rotational speed of the first motor generator MG1 is changed from the rotational speed mc1 in the normal rotational direction to the rotational speed “0”. After the control, the clutch 7a is engaged. At this time, the alignment chart changes from the straight line Ac1 to the straight line As1, and the engine speed changes from the engine speed Nec1 in the continuously variable transmission mode to the engine speed Nes1 in the fixed speed change mode. In the following, the engine speed in the continuously variable transmission mode is referred to as “the continuously variable speed mode rotational speed”, and the engine rotational speed in the fixed transmission mode is referred to as “fixed transmission mode rotational speed”. In the example illustrated in FIG. 4, the rotation speeds Nes 1 and Nes 2 in the fixed transmission mode are engine rotation speeds when the rotation speed of the first motor generator MG 1 is “0”.

  Next, the case where first motor generator MG1 is in the negative rotation in the continuously variable transmission mode will be described. In this case, when the ECU 4 determines that the vehicle operating point has moved to the fixed speed change mode region Ars, the rotational speed of the first motor generator MG1 is changed from the rotational speed mc2 in the negative rotational direction to the rotational speed “0”. After the control, the clutch 7a is engaged. At this time, the nomograph changes from the straight line Ac2 to the straight line As2, and the engine speed changes from the continuously variable speed mode speed Nec2 to the fixed speed mode speed Nes2.

  As described above, in the general shift mode switching control method, the ECU 4 determines that the vehicle operating point has moved to the fixed shift mode region Ars, and then sets the rotation speed of the first motor generator MG1 to “0”. To engage the clutch 7a. When this shift mode switching control method is used, the time during which the clutch 7a is engaged is equal to the time required for the shift mode switching control compared to the time during which the vehicle operating point is located in the fixed shift mode region Ars. May become shorter and fuel consumption may deteriorate. Further, the ECU 4 determines that the vehicle operating point has moved to the fixed speed change mode region Ars, and then suddenly and greatly changes the engine speed from the continuously variable speed mode speed to the fixed speed mode speed. As a result, drivability may be degraded.

  Therefore, in the shift mode switching control method according to the first embodiment, the ECU 4 determines that the vehicle operating point has moved from the continuously variable shift mode area Arc to the transition area Arr based on the shift mode determination map shown in FIG. In such a case, the engine speed is brought closer to the fixed speed mode rotation speed at a certain rate. For example, the ECU 4 sets the difference between the rotation speed in the continuously variable transmission mode and the rotation speed in the fixed transmission mode as 100%, when the vehicle operating point moves from the continuously variable transmission mode area Arc to the transition area Arr, The engine speed is changed at a rate of 50% every time when is moved from the transition area Arr to the fixed speed change mode area Ars.

  FIG. 5 shows how the nomograph changes during the shift mode switching control according to the first embodiment. In FIG. 5, straight lines Ar <b> 1 and Ar <b> 2 are collinear diagrams when the vehicle operating point is located in the transition region Arr.

  First, the case where first motor generator MG1 is rotating forward in the continuously variable transmission mode will be described. In this case, when the ECU 4 determines that the vehicle operating point has moved from the continuously variable transmission mode area Arc to the transition area Arr, the ECU 4 decreases the engine speed by (Nec1-Nes1) × 0.50 and in the continuously variable transmission mode. The rotational speed Nec1 is changed to the rotational speed Ner1. Further, when the ECU 4 determines that the vehicle operating point has moved from the transition area Arr to the fixed speed change mode area Ars, the ECU 4 decreases the engine speed by (Nec1-Nes1) × 0.50 and fixes it from the speed Ner1. The speed is changed to the rotation speed Nes1 in the shift mode.

  Next, the case where first motor generator MG1 is in the negative rotation in the continuously variable transmission mode will be described. In this case, when the ECU 4 determines that the vehicle operating point has moved from the continuously variable transmission mode area Arc to the transition area Arr, the ECU 4 increases the engine speed by (Nes2-Nec2) × 0.50 and in the continuously variable transmission mode. The rotational speed Nec2 is changed to the rotational speed Ner2. Further, when the ECU 4 determines that the vehicle operating point has moved from the transition area Arr to the fixed speed change mode area Ars, the ECU 4 increases the engine speed by (Nes2-Nec2) × 0.50 and fixes it from the speed Ner2. The speed is changed to the speed Nes2 in the shift mode.

  FIG. 6 is a diagram showing the movement of the operating point (engine operating point) of the engine 1 determined by the engine torque and the engine speed according to the first embodiment described above, and the vertical axis indicates the engine torque. The horizontal axis indicates the engine speed.

  FIG. 6 shows an operation line Lc in the continuously variable transmission mode (hereinafter referred to as “CVT operation line”), an operation line Ls in the fixed transmission mode, equal power lines Lp1, Lp2, and an equal efficiency line B4. Yes. The CVT operation line Lc is defined so as to be optimal from the viewpoint of improving fuel consumption, for example. In the continuously variable transmission mode, the engine operating point moves on the CVT operation line Lc, and in the fixed transmission mode, the engine operating point moves on the operation line Ls.

  In FIG. 6, points Pec1 and Pec2 on the CVT operation line Lc are engine operating points when the engine speed becomes the infinitely variable speed mode speeds Nec1 and Nec2, respectively. Further, points Pes1 and Pes2 on the operating line Ls are engine operating points when the engine speed becomes the fixed speed mode speed Nes1 and Nes2, respectively. Further, the points Per1 and Per2 are engine operating points when the engine rotational speed is the rotational speeds Ner1 and Ner2, respectively.

  First, the case where first motor generator MG1 is rotating forward in the continuously variable transmission mode will be described. In this case, when the vehicle operating point moves from the continuously variable transmission mode area Arc to the transition area Arr, the ECU 4 reduces the engine speed to change from the continuously variable speed mode rotation speed Nec1 to the rotation speed Ner1. Change. At this time, the ECU 4 controls the engine 1 so that the engine operating point moves from the point Pec1 to the point Per1 along the equal power line Lp1. Further, when the vehicle operating point moves from the transition area Arr to the fixed speed change mode area Ars, the ECU 4 further reduces the engine speed to change from the speed Ne1 to the speed Nes1 in the fixed speed mode. At this time, the ECU 4 controls the engine 1 so that the engine operating point moves from the point Per1 to the point Pes1 along the equal power line Lp1. Thus, the driving force can be kept constant by controlling the engine 1 so that the engine operating point moves along the equal power line.

  Next, the case where first motor generator MG1 is in the negative rotation in the continuously variable transmission mode will be described. In this case, when the vehicle operating point moves from the continuously variable transmission mode area Arc to the transition area Arr, the ECU 4 increases the engine speed to change from the continuously variable speed mode rotation speed Nec2 to the rotation speed Ner2. Change. At this time, the ECU 4 controls the engine 1 so that the engine operating point moves from the point Pec2 to the point Per2 along the equal power line Lp2. Further, when the vehicle operating point moves from the transition area Arr to the fixed speed change mode area Ars, the ECU 4 further increases the engine speed to change from the speed Ne2 to the speed Nes2 in the fixed speed mode. At this time, the ECU 4 controls the engine 1 so that the engine operating point moves from the point Per2 to the point Pes2 along the equal power line Lp2.

  In other words, according to the shift mode switching control method according to the first embodiment, when it is determined that the vehicle operating point is located in the fixed shift mode region Ars, the engine speed is already set to a fixed rate by the engine in the fixed shift mode. The speed is approaching. Therefore, compared with a general shift mode switching control method, according to the shift mode switching control method according to the first embodiment, the first operation after the vehicle operating point is determined to have moved to the fixed shift mode region Ars. The time until the rotational speed of motor generator MG1 is set to the rotational speed “0” can be shortened, and the time during which clutch 7a is actually engaged can be lengthened. Further, as compared with the general shift mode switching control method, according to the shift mode switching control method according to the first embodiment, the engine rotation after it is determined that the vehicle operating point has moved to the fixed shift mode region Ars. The amount to be changed can be reduced, and the drivability can be prevented from being lowered.

[Second Embodiment]
First, the control method of the hybrid vehicle which concerns on 2nd Embodiment of this invention is demonstrated.

  As can be seen from FIG. 6 in the first embodiment, the points Per1 and Per2 are separated from the points Pec1 and Pec2 on the CVT operation line Lc, respectively. That is, when the vehicle operating point moves from the continuously variable transmission mode area Arc to the transition area Arr, the engine operating point leaves the CVT operating line Lc. In the continuously variable transmission mode, the fuel efficiency worsens as the engine operating point is further away from the CVT operation line Lc.

  Thus, in the shift mode switching control method according to the second embodiment, when the vehicle operating point is located in the transition region, the ECU 4 rotates in the fixed shift mode as the vehicle operating point approaches the fixed shift mode region Ars. The ratio at which the engine speed approaches the number is increased. Hereinafter, it demonstrates concretely using FIGS.

  FIG. 7 is a diagram showing the movement of the vehicle operating point on the map defined by the vehicle speed and the accelerator opening, where the vertical axis shows the accelerator opening and the horizontal axis shows the vehicle speed. Vehicle operating points are indicated by white circles.

  On the map shown in FIG. 7, a fixed transmission mode area Ars and a continuously variable transmission mode area Arc are set. On the map, a transition region Arr is set in the continuously variable transmission mode region Arc adjacent to the fixed transmission mode region Ars. The transition region Arr is composed of transition regions Arr1, Arr2, and Arr3. As indicated by the arrow W, when the vehicle operating point moves from the continuously variable transmission mode region Arc to the fixed transmission mode region Ars, the ECU 4 is fixed as the vehicle operating point moves to the transition regions Arr1, Arr2, and Arr3. The ratio at which the engine speed approaches the speed in the shift mode is increased.

  FIG. 8 shows how the nomograph changes during the shift mode switching control according to the second embodiment. In FIG. 8, straight lines Ar11 and Ar21 are collinear diagrams when the vehicle operating point is located in the transition region Arr1, and straight lines Ar12 and Ar22 are collinear diagrams when the vehicle operating point is located in the transition region Arr2. Yes, straight lines Ar13 and Ar23 are collinear diagrams when the vehicle operating point is located in the transition region Arr3.

  When the vehicle operating point moves to the transition areas Arr1, Arr2, and Arr3, the ECU 4 changes the engine speed by the ratios f1, f2, and f3, respectively. Specifically, the ECU 4 actually changes the difference between the rotation speed in the continuously variable transmission mode and the rotation speed in the fixed transmission mode to 100%, for example, f1 is 10%, f2 is 20%, and f3 is 30%. Determine the amount of change in rotation speed. That is, the ratios f1, f2, and f3 of the rotation speed to be changed are set so as to satisfy the relationship of f3> f2> f1. The remaining 40% is the ratio of the engine speed that is changed when the vehicle operating point moves from the transition area Arr3 to the fixed speed change mode area Ars. Thus, in the second embodiment, the closer the vehicle operating point is to the fixed shift mode region Ars, the greater the ratio of the engine speed approaching the fixed shift mode speed.

  As an example, the engine speed change in the case where f1 is 10%, f2 is 20%, and f3 is 30% will be described.

  First, the case where first motor generator MG1 is rotating forward in the continuously variable transmission mode will be described. In this case, when the ECU 4 determines that the vehicle operating point has moved from the continuously variable transmission mode area Arc to the transition area Arr1, the engine speed is decreased by (Nec1-Nes1) × 0.10 to thereby change the continuously variable transmission mode. The rotational speed Nec1 is changed to the rotational speed Ner11. When the ECU 4 determines that the vehicle operating point has moved from the transition region Arr1 to the transition region Arr2, the ECU 4 decreases the engine speed by (Nec1-Nes1) × 0.20 and changes the engine speed from the rotation speed Ner11 to the rotation speed Ner12. . When the ECU 4 determines that the vehicle operating point has moved from the transition region Arr2 to the transition region Arr3, the ECU 4 decreases the engine speed by (Nec1-Nes1) × 0.30 and changes the engine speed from the rotation speed Ner12 to the rotation speed Ner13. . If the ECU 4 determines that the vehicle operating point has moved from the transition area Arr3 to the fixed speed change mode area Ars, the ECU 4 decreases the engine speed by (Nec1-Nes1) × 0.40 and starts from the speed Ner13 to the speed in the fixed speed change mode. Change to Nes1.

  Next, the case where first motor generator MG1 is in the negative rotation in the continuously variable transmission mode will be described. In this case, if the ECU 4 determines that the vehicle operating point has moved from the continuously variable transmission mode area Arc to the transition area Arr1, the ECU 4 increases the engine speed by (Nes2-Nec2) × 0.10 to increase the continuously variable transmission mode. The rotational speed Nec2 is changed to the rotational speed Ner21. When the ECU 4 determines that the vehicle operating point has moved from the transition area Arr1 to the transition area Arr2, the ECU 4 increases the engine speed by (Nes2-Nec2) × 0.20 and changes the speed from the speed Ner21 to the speed Ner22. . When the ECU 4 determines that the vehicle operating point has moved from the transition area Arr2 to the transition area Arr3, the ECU 4 increases the engine speed by (Nes2-Nec2) × 0.30 and changes the speed from the speed Ner22 to the speed Ner23. . When the ECU 4 determines that the vehicle operating point has moved from the transition area Arr3 to the fixed speed change mode area Ars, the ECU 4 increases the engine speed by (Nes2-Nec2) × 0.40 and starts from the speed Ner23 to the speed in the fixed speed change mode. Change to Nes2.

  FIG. 9 is a diagram showing the movement of the engine operating point determined by the engine torque and the engine speed, as in FIG. In FIG. 9, points Per11, Per12, and Per13 are engine operating points when the engine speed becomes the rotation speeds Ner11, Ner12, and Ner13, respectively. Further, points Per21, Per22, and Per23 are engine operating points when the engine speed becomes the rotational speeds Ner21, Ner22, and Ner23, respectively.

  First, the case where first motor generator MG1 is rotating forward in the continuously variable transmission mode will be described. In this case, when the vehicle operating point moves from the continuously variable transmission mode region Arc to the fixed transmission mode region Ars through the transition regions Arr1, Arr2, and Arr3, as described above, the ECU 4 Are sequentially changed from the rotation speed Nec1 in the continuously variable transmission mode to the rotation speeds Ner11, Ner12, and Ner13, and changed to the rotation speed Nes1 in the fixed transmission mode. At this time, the ECU 4 controls the engine 1 such that the engine operating point moves along the isopower line Lp1 from the point Pec1 to the point Pes1, via the points Per11, Per12, and Per13. Thus, by controlling the engine 1 so that the engine operating point moves along the equal power line, the driving force can be kept constant.

  Next, the case where first motor generator MG1 is in the negative rotation in the continuously variable transmission mode will be described. In this case, when the vehicle operating point moves from the continuously variable transmission mode region Arc to the fixed transmission mode region Ars through the transition regions Arr1, Arr2, and Arr3, as described above, the ECU 4 Are sequentially changed from the rotation speed Nec2 in the continuously variable transmission mode to the rotation speeds Ner21, Ner22, and Ner23, and then to the rotation speed Nes2 in the fixed transmission mode. At this time, the ECU 4 controls the engine 1 such that the engine operating point moves from the point Pec2 to the point Pes2 along the equipower line Lp2 through the points Per21, Per22, and Per23.

  As described above, in the shift mode switching control method according to the second embodiment, the ECU 4 increases the ratio of the engine speed closer to the fixed shift mode rotation speed as the vehicle operating point approaches the fixed shift mode area Ars. It is getting bigger. Conversely, as the vehicle operating point approaches the continuously variable transmission mode area Arc, the ECU 4 decreases the rate at which the engine rotational speed approaches the rotational speed in the fixed transmission mode. As a result, the engine operating point approaches the CVT operation line Lc as the vehicle operating point approaches the continuously variable transmission mode region Arc. For example, in the case where the vehicle operating point is located in the transition region Arr1, compared to the engine operating points Per1 and Per2 when the vehicle operating point is located in the transition region Arr as described in the first embodiment (see FIG. 6). Engine operating points Per11 and Per21 (see FIG. 9) are closer to the CVT operating line Lc. Therefore, according to the shift mode switching control method according to the second embodiment, it is possible to suppress deterioration in engine efficiency as compared with the shift mode switching control method according to the first embodiment.

  That is, according to the shift mode switching control method according to the second embodiment, the effect of the shift mode switching control method according to the first embodiment, that is, the time during which the clutch 7a is actually engaged can be lengthened. And in addition to the effect that the drivability fall can be prevented, engine efficiency deterioration can also be suppressed.

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

  Further, as a hybrid vehicle mechanism to which the present invention can be applied, a mechanism for realizing the fixed shift mode by locking the rotor of the first motor generator MG1, that is, by fixing the sun gear S1. Not limited. Instead, the present invention can be applied even to a mechanism that realizes the fixed transmission mode by fixing any one of the rotating elements of the power distribution mechanism 20 other than the sun gear S1 with a brake. .

It is a figure showing the schematic structure of the hybrid vehicle concerning each 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 mode of the movement of the vehicle operating point which concerns on 1st Embodiment. It is a figure which shows an example of the change of a nomograph when changing from continuously variable transmission mode to fixed transmission mode. It is a figure which shows an example of the change of an alignment chart when changing from the continuously variable transmission mode which concerns on 1st Embodiment to fixed transmission mode. It is a figure which shows the movement of an engine operating point when changing from the continuously variable transmission mode which concerns on 1st Embodiment to fixed transmission mode. It is a figure which shows the mode of the movement of the vehicle operating point which concerns on 2nd Embodiment. It is a figure which shows an example of the change of an alignment chart when changing from the continuously variable transmission mode which concerns on 2nd Embodiment to fixed transmission mode. It is a figure which shows the movement of an engine operating point when changing from the continuously variable transmission mode which concerns on 2nd Embodiment to fixed transmission mode.

Explanation of symbols

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

Claims (3)

This is applied to a hybrid vehicle having a driving force source and configured to be able to switch between two speed modes, a continuously variable transmission mode and a fixed transmission mode, and a continuously variable transmission mode area and a fixed transmission mode area are set. Further, on the map defined by the accelerator opening and the vehicle speed, a control device for a hybrid vehicle comprising control means for switching the shift mode according to the position of the vehicle operating point,
On the map, a transition region is set adjacent to the fixed shift mode region to bring the rotation number of the driving force source closer to the fixed shift mode rotation number that is the rotation number of the driving force source in the fixed shift mode.
When the vehicle operating point is located in the transition region, the control means brings the rotational speed of the driving force source closer to the rotational speed in the fixed transmission mode as the vehicle operating point approaches the fixed transmission mode area. A control device for a hybrid vehicle, characterized by increasing a ratio. The hybrid vehicle includes an engine as a driving force source, 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. An engagement mechanism coupled to any rotating element in the mechanism and fixing or releasing the rotating element;
The control means switches the transmission mode between the fixed transmission mode and the continuously variable transmission mode by fixing or releasing the rotating element by the engagement mechanism,
2. The control apparatus for a hybrid vehicle according to claim 1, wherein the rotation speed in the fixed speed change mode is an engine rotation speed when a rotation speed of a rotation element connected to the engagement mechanism becomes zero.   The control means moves the engine operating point along an equal power line on a map defined by the engine speed and the engine torque when the engine speed is brought close to the engine speed in the fixed shift mode. The control apparatus for a hybrid vehicle according to claim 2.

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