JP2007118716A - Controller for drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a drive unit capable of restraining a temperature of an electric motor from being elevated in accompaniment to shift transmission control. <P>SOLUTION: This controller for the drive unit is provided with a power distribution mechanism for distributing power output from a prime mover to the electric motor an an output member, and a transmission transmitted with the power from the output member, and allows a continuously variable speed change of maintaining a substantially constant rotation speed of the prime mover, and a multistage speed change of changing the rotation speed of the prime mover. The controller is provided with a temperature determination means (step S2) for detecting or predicting a temperature in at least one out of the respective electric motors, and a shift transmission mode selection means (steps S3-S6) for selecting either of the continuously variable speed change or the multistage speed change, as the shift transmission mode to be executed based on the temperature detected or predicted by the temperature determination means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive device including a power distribution mechanism that controls the rotational speed of a prime mover such as an internal combustion engine in accordance with the rotational speed of an electric motor and a transmission, and more particularly to a control device that performs the shift control.

  This type of driving device is described in Patent Document 1 and Patent Document 2. The hybrid drive device described in Patent Document 1 includes a power distribution mechanism mainly composed of a planetary gear mechanism that distributes the power output by the engine to the first electric motor having a power generation function and the output side portion. A second motor that adds torque to the output torque by connecting a transmission such as a stepped automatic transmission to the output side member and supplying electric power generated by the first motor to function as a motor. Is provided.

The hybrid drive device described in Patent Document 2 includes a planetary gear mechanism that can be switched between a direct-coupled stage that outputs the power output from the engine as it is and a low-speed stage that outputs the reduced speed and outputs the planetary gear mechanism. A power distribution mechanism mainly including a planetary gear mechanism that distributes the generated power to the first electric motor and the output side member, and the electric power generated by the first electric motor is supplied to function as a motor to output A second electric motor that adds torque to the torque is provided. And in invention of this patent document 2, it controls so that transmission of the motive power which is not accompanied by power conversion, ie, direct torque, is increased.
JP 2003-130202 A JP 2000-346187 A

  In the hybrid drive device described in Patent Document 1, the transmission gear ratio is changed according to the vehicle speed, and in the hybrid drive device described in Patent Document 2, it is arranged on the output side of the engine. Since the planetary gear mechanism is switched between a direct connection stage and a low speed stage according to the vehicle speed, power transmission accompanied by power conversion, that is, power transmission by an electric path is suppressed, and as a result, overall power transmission efficiency is improved. . However, there are various driving conditions of the vehicle, and in addition to the driving condition where the power transmission by the electric path is almost zero, a part of the power output by the engine is transmitted to the output shaft via the power distribution mechanism and the transmission. On the other hand, after the other part of the motive power output from the engine is converted into electric power, the motor may travel by being converted again into mechanical power by the motor and transmitted to the output shaft.

  In this case, there is a loss due to power conversion, so that the power transmission efficiency as a whole decreases, and particularly when the vehicle travels at a speed ratio intermediate between the gears set by the transmission and the planetary gear mechanism, the power transmission efficiency decreases. To do. Then, if the power output from the engine is converted into electric power and converted back into mechanical power again, heat is inevitably generated in the electric motor that functions as a generator and the electric motor that functions as a motor. Due to the above restrictions, there is a possibility that the intended control cannot be performed or the durability is lowered.

  The present invention has been made paying attention to the above technical problem, and an object of the present invention is to provide a control device for a drive device that can suppress an increase in the temperature of an electric motor accompanying shift control.

  In order to achieve the above object, the invention of claim 1 includes a power distribution mechanism that distributes the power output from the prime mover to the electric motor and the output member, and a transmission to which the power is transmitted from the output member, Temperature determining means for detecting or predicting the temperature of the electric motor in a control device for a driving device capable of continuously variable transmission for maintaining the rotational speed of the prime mover substantially constant and multi-stage transmission for changing the rotational speed of the prime mover And a shift mode selection unit that selects either the stepless shift or the multi-step shift as a shift mode to be executed based on the temperature detected or predicted by the temperature determination unit. It is characterized by.

  According to a second aspect of the present invention, in the first aspect of the invention, the shift mode selection means includes means for selecting a multi-stage shift when the temperature detected or predicted by the temperature determination means is higher than a determination reference value. A control device for a drive device characterized by the above.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the speed change mode selecting means increases the ratio of the rotational speed of the prime mover before and after the speed change as the temperature detected or predicted by the temperature determining means increases. A control device for a drive device, comprising means for selecting a multi-stage gear shift that increases.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the multi-stage shift is performed by increasing the vehicle speed while maintaining the rotational speed of the prime mover at a predetermined rotational speed by the electric motor. After the ratio between the rotational speed of the prime mover and the output shaft rotational speed reaches a predetermined value, the rotational speed of the prime mover is increased so as to maintain the ratio at a constant value, and the rotational speed of the prime mover increases to a predetermined value. The drive device control device is characterized in that the gear ratio of the transmission is changed stepwise at a time.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the multi-stage shift is performed by reducing the vehicle speed while maintaining the rotational speed of the prime mover at a predetermined rotational speed by the electric motor. After the ratio of the rotational speed of the prime mover and the output shaft rotational speed reaches a predetermined value, the rotational speed of the prime mover is decreased so that the ratio is maintained at a constant value, and the rotational speed of the prime mover is decreased to a predetermined value. The drive device control device is characterized in that the gear ratio of the transmission is changed stepwise at a time.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the operating point of the prime mover after the multi-stage shifting is set as an operating point on the lower rotational speed and higher torque side than the optimum fuel consumption point in the output. And a drive control device further comprising prime mover control means for increasing the rotational speed of the prime mover so that the ratio between the rotational speed of the prime mover and the output shaft rotational speed becomes constant as the vehicle speed increases. is there.

  According to a seventh aspect of the present invention, in any one of the first to fifth aspects, the operating point of the prime mover after the multi-stage shifting is set as an operating point on the high rotational speed and low torque side from the optimum fuel consumption point in the output. And a control device for the drive device, further comprising another prime mover control means for reducing the prime mover rotational speed so that the ratio of the prime mover rotational speed and the output shaft rotational speed becomes constant as the vehicle speed decreases It is.

  According to an eighth aspect of the present invention, in the sixth or seventh aspect of the present invention, when the power loss due to the motor is small when the prime mover control means changes the operating point of the prime mover to the optimum fuel consumption point, A drive device control device comprising means for executing a stepless speed change that continuously changes the rotational speed of a prime mover.

  According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the multistage shift is such that the power loss due to the motor before the upshift is equal to the power loss due to the motor before the downshift. A control device for a drive device, characterized in that the speed change is executed at a provided shift point.

  According to a tenth aspect of the present invention, there is provided a control apparatus for a driving apparatus according to any one of the first to ninth aspects, wherein the prime mover includes an internal combustion engine that burns fuel and outputs power.

  An eleventh aspect of the invention is a drive device control apparatus according to any one of the first to tenth aspects, wherein the electric motor includes an electric motor having a power generation function.

  According to a twelfth aspect of the present invention, in the invention of the eleventh aspect, the drive device is provided with another electric motor that adds torque to the output torque when the electric power generated by the electric motor is supplied to operate. It is a control apparatus of the drive device characterized by including an apparatus.

  According to the first aspect of the present invention, either the stepless speed change or the multi-stage speed change is selected according to the detected temperature or the predicted temperature of the electric motor. For example, when the temperature is high The multi-stage shift is selected. Therefore, the transmission state of power using the electric motor, that is, the transmission amount of power by a so-called electric path is suppressed, and the temperature rise of the electric motor can be prevented or suppressed.

  According to the invention of claim 2, when the temperature is higher than the judgment reference value, the multi-stage shift is selected. Therefore, the transmission state of power using the electric motor, that is, the transmission amount of power by a so-called electric path is suppressed, and the temperature rise of the electric motor can be prevented or suppressed.

  According to the invention of claim 3, when the temperature is high, the multi-stage gear shift is executed so that the ratio of the rotational speed of the prime mover before and after the gear shift becomes larger than when the temperature is low. Therefore, the transmission of power by the electric path in the transition state of the shift is relatively reduced, and as a result, the temperature rise of the motor can be prevented or suppressed.

  According to the fourth aspect of the present invention, the speed of the output shaft increases with respect to the speed of the prime mover maintained by the electric motor at the time of speed change (for example, upshift) accompanying the increase in the vehicle speed. When the ratio reaches a predetermined value, the rotational speed of the prime mover is changed so that the value is maintained. After that, the rotational speed of the prime mover reaches the predetermined value. The gear ratio is changed stepwise to execute multi-stage gear shifting. As a result, the rate at which the electric motor is operated is relatively reduced, and efficient operation can be performed.

  According to the fifth aspect of the present invention, the output shaft rotational speed decreases with respect to the rotational speed of the prime mover maintained by the electric motor at the time of speed change (for example, downshift) accompanying the decrease in the vehicle speed. When the ratio reaches a predetermined value, the rotational speed of the prime mover is changed so that the value is maintained. After that, the rotational speed of the prime mover reaches the predetermined value. The gear ratio is changed stepwise to execute multi-stage gear shifting. As a result, the rate at which the electric motor is operated is relatively reduced, and efficient operation can be performed.

  According to the sixth aspect of the present invention, the speed of the prime mover is temporarily changed to the low torque high torque side at the time of shifting accompanying the increase of the vehicle speed, without maintaining the optimum fuel consumption point, thereby increasing the vehicle speed. Along with this, the motor speed is increased so that the ratio between the motor speed and the output shaft speed is constant, so that the motor speed can be decreased and the output and loss of the motor can be reduced accordingly. it can.

  According to the seventh aspect of the present invention, the speed of the prime mover is temporarily changed to the high torque and low torque side without changing the rotational speed of the prime mover at the optimum fuel consumption point at the time of the shift accompanying the decrease in the vehicle speed, thereby reducing the vehicle speed. Along with this, the rotational speed of the prime mover is reduced so that the ratio between the rotational speed of the prime mover and the output shaft rotational speed is constant, so that the rotational speed of the motor can be reduced, and accordingly the output and loss of the motor can be reduced. it can.

  According to the eighth aspect of the present invention, when the operating point of the prime mover becomes the optimum fuel consumption point, and when the loss due to the motor is small, the stepless speed change that continuously changes the rotational speed of the prime mover is executed by the motor. Therefore, fuel consumption can be improved and power loss due to the electric motor can be reduced.

  According to the invention of claim 9, in the case of downshift and upshift by multi-stage shift, the shift point is set so that the loss due to the motor becomes equal at the shift point at which these shifts are executed. The maximum loss can be reduced.

  According to the invention of claim 10, in addition to the same effects as the effects of the inventions of the above-mentioned claims, the fuel consumption of the drive device using the internal combustion engine as a power source can be improved.

  According to the eleventh aspect of the present invention, in addition to the same effects as the effects of the above-mentioned respective inventions, the power output from the prime mover can be effectively used to improve the energy efficiency.

  According to the twelfth aspect of the present invention, in addition to obtaining the same effects as the effects of the above-described respective inventions, the power output from the prime mover can be converted into electric power and transmitted to the output side. The power performance can be improved.

  Next, the present invention will be described based on specific examples. First, an example of a hybrid vehicle drive device that can be targeted by the control device of the present invention will be described. The example shown in FIG. 9 is an example of being mounted on a hybrid vehicle (hereinafter abbreviated as “vehicle”) Ve of FR type (front engine / rear drive; engine front and rear wheel drive) type. The drive device shown in FIG. 9 has two types of power sources. The two types of power sources have different power generation principles. In this embodiment, the engine 1 and the motor / generator (MG2) 2 are mounted as power sources and output from the engine 1 and the motor / generator 2. The power train and the power transmission path are configured so that the power is transmitted to the same wheel (rear wheel) 3 together. The engine 1 that is the prime mover of the vehicle Ve is a power device that burns fuel and converts the heat energy into kinetic energy. As the engine 1, an internal combustion engine or an external combustion engine can be used. In this embodiment, a case where an internal combustion engine such as a gasoline engine, a diesel engine, an LPG engine, or the like is used as the engine 1 will be described. The engine 1 has an output control device such as an electronic throttle valve (not shown), a fuel injection device (not shown), an ignition timing control device (not shown), and controls at least one device. Thus, the engine output can be controlled.

  On the other hand, the motor / generator 2 which is another power source is housed in the casing 4. The motor / generator 2 has a power running function for converting electric energy into kinetic energy and a regenerative function for converting kinetic energy into electric energy. Combines functionality. The motor / generator 2 includes a rotor 5 and a stator 6, and the stator 6 is fixed to the casing 4. A transmission (AT unit) 7 is provided in a power transmission path from the engine 1 and the motor / generator 2 to the wheels 3, and a power distribution device is provided in the power transmission path from the engine 1 to the transmission 7. 8 is provided. The power distribution device 8 shown in FIG. 9 is mainly composed of a single pinion type planetary gear mechanism. That is, the power distribution device 8 includes a sun gear 10 disposed coaxially with the output shaft 9 of the engine 1, a ring gear 11 disposed coaxially with the sun gear 10, and a plurality of pinion gears 12 meshing with the sun gear 10 and the ring gear 11. And a carrier 13 which holds the motor so as to rotate and revolve freely.

  The sun gear 10, the ring gear 11, and the carrier 13 are configured to be differentially rotatable with respect to each other. The carrier 13 and the output shaft 9 are coupled so as to be able to transmit power, and are specifically coupled so as to rotate integrally. In the axial direction of the output shaft 9, a motor / generator (MG1) 14 is disposed between the engine 1 and the power distribution device 8 as an electric motor having a power generation function. The motor / generator 14 has both a power running function that converts electrical energy into kinetic energy and a regeneration function that converts kinetic energy into electrical energy. The motor / generator 14 includes a rotor 15 and a stator 16, and the stator 16 is fixed to the casing 4. The rotor 15 and the sun gear 10 are coupled so as to be able to transmit power, and are specifically coupled so as to rotate integrally.

  On the other hand, the transmission 7 is configured to be capable of changing (controlling) a transmission gear ratio that is a value obtained by dividing the input rotation speed by the output rotation speed. In this embodiment, a case where a stepped transmission is used as the transmission 7, more specifically, a case where a stepped transmission having a planetary gear mechanism is used will be described. The transmission 7 has a friction engagement device, specifically a clutch and a brake, for switching the power transmission path between the rotating elements constituting the planetary gear mechanism and controlling the rotation / stop of the rotating elements. Yes. Here, either a hydraulic control type or an electromagnetic control type may be used as the friction engagement device, but in this embodiment, a case where a hydraulic control type friction engagement device is used will be described. By controlling the engagement / release of these friction engagement devices, for example, the first to sixth speeds can be selected at the drive position, and the fixed gear ratio can be selected at the reverse position. Yes. When the drive position is selected, the first to sixth gears can be changed selectively and stepwise. Further, the gear ratio of the transmission 7 is configured to be smaller as the number indicating the gear stage is larger.

  A rotating member 29 is connected to the input side of the transmission 7, and an output rotating member (output shaft) 30 is connected to the output side of the transmission 7. Further, the input rotation member 29 and the ring gear 11 of the power distribution device 8 are connected so as to rotate integrally, and the rotor 5 of the motor / generator 2 is connected to the input rotation member 29. The output rotating member 30 is a so-called propeller shaft, and the output rotating member 30 is connected to a drive pinion shaft (not shown) of the differential 31. A drive shaft 32 is connected to a side gear (not shown) of the differential 31, and the wheel 3 is connected to the drive shaft 32.

  Further, a power storage device 33 capable of transferring power to and from the motor / generator 2 is provided, and an inverter 34 is provided in a circuit between the motor / generator 2 and the power storage device 33. Yes. A power storage device 35 capable of transferring power to and from the motor / generator 14 is provided, and an inverter 36 is provided in a circuit between the motor / generator 14 and the power storage device 35. Yes. As these power storage devices 33 and 35, secondary batteries, specifically, batteries, capacitors, and the like can be used. In addition, an electric circuit 39 that connects the inverter 34 and the inverter 36 is provided. The electric circuit 39 is configured to be able to transfer power between the power storage device 33 and the power storage device 35, and the motor generator 2. Between the motor and the generator 14 can be exchanged without passing through the power storage devices 33 and 35.

  On the other hand, in order to execute control of the transmission 7, for example, control for switching a shift position such as a drive position, a reverse position, a neutral position, a manual position, an automatic shift control of a shift stage when the drive position is selected, A hydraulic control device 37 is provided. The hydraulic control device 37 has a known configuration including a hydraulic circuit, a manual valve, a solenoid valve, a pressure control valve, and the like. The hydraulic control device 37 switches each shift position, and the friction engagement described above. Engagement / release of the device is controlled.

  Next, the control system will be described. First, an electronic control unit 38 is provided. The electronic control unit 38 includes a shift position sensor signal, a vehicle speed sensor signal, an acceleration request detection sensor signal, a braking request detection sensor signal, and an engine speed sensor signal. , A sensor signal for detecting the amount of charge of the power storage devices 33 and 35, a sensor signal for detecting the rotation speed of the motor / generators 2 and 14, a sensor signal for detecting the temperature of the motor / generators 2 and 14, and an input rotating member 29, a sensor signal for detecting the rotational speed of the output rotating member 30, a sensor signal for detecting the gradient of the road on which the vehicle Ve travels, a sensor signal for detecting the acceleration of the vehicle Ve, and the like are input. On the other hand, the electronic control device 38 outputs a signal for controlling the engine 1, a signal for controlling the motor / generators 2 and 14 (inverters 34 and 36), a signal for controlling the hydraulic pressure control device 37, and the like.

  In the vehicle Ve shown in FIG. 9, when the engine 1 is operated and the engine torque is transmitted to the carrier 13 of the power distribution device 10, the reaction torque is received by the motor / generator 14, and the engine torque becomes the ring gear 11. Is transmitted to. The torque transmitted to the ring gear 11 is transmitted to the wheel 3 via the input rotating member 29, the transmission 7, the output rotating member 30, and the differential 31, and a driving force is generated. In the power distribution device 8, it is possible to control the gear ratio between the carrier 13 as an input element and the ring gear 11 as an output element by the differential action of the sun gear 10, the carrier 13 and the ring gear 11. Specifically, the engine speed can be controlled steplessly (continuously) by controlling the output of the motor / generator 14 responsible for the reaction force torque. That is, the power distribution device 8 has a function as a continuously variable transmission (electric CVT unit).

  As described above, when the motor / generator 14 takes charge of reaction force torque, the rotation direction of the motor / generator 14 is selectively switched to forward rotation, stop, reverse rotation, and the like based on various conditions. For example, when the motor / generator 14 rotates forward and takes on the reaction torque, the motor / generator 14 is regeneratively controlled, and the electric power generated by the motor / generator 14 is charged into the power storage device 35 or the inverters 36 and 34 are connected. The motor / generator 2 can be supplied to the motor / generator 2 for power running control. That is, the motor / generator 2 is driven as an electric motor, and the torque is transmitted to the wheels 3 via the input rotating member 29, the transmission 7, and the differential 31. On the other hand, when the motor / generator 14 rotates in the reverse direction and takes charge of the reaction torque, the motor / generator 14 is subjected to power running control. The electric power supplied to the motor / generator 14 can be supplied from the power storage device 35 or the motor / generator 2. That is, the motor / generator 2 can be regeneratively controlled and the electric power can be supplied to the motor / generator 14 via the inverters 34 and 36.

  Here, the concept of controlling the speed ratio of the power distribution device 8 will be described. For the purpose of improving the fuel consumption of the engine 1, the operating state of the engine 1 and the speed ratio of the power distribution device 8 are controlled in a coordinated manner. It is. For example, the required driving force in the vehicle Ve is obtained based on the acceleration request (accelerator opening) and the vehicle speed. This is obtained from a map prepared in advance, for example. The required output of the engine 1 is calculated from the required driving force and the vehicle speed, and the target engine speed that outputs the required output with the minimum fuel consumption is obtained using the map. Then, the output (torque × rotational speed) of the motor / generator 14 is controlled so that the actual engine rotational speed approaches the target engine rotational speed with good fuel efficiency. In parallel with this control, the opening degree of the electronic throttle valve of the engine 1 is controlled so that the actual engine output approaches the target engine output. Thus, by controlling the gear ratio of the power distribution device 8, the operating state of the engine 1 can be controlled along the optimum fuel consumption line.

  Further, as described above, it is possible to execute control in which the motor / generator 2 is driven as an electric motor and the torque of the motor / generator 2 is transmitted to the wheels 3 via the transmission 7. That is, when torque is transmitted to the wheel 3 to generate driving force, at least one torque of the engine 1 or the motor / generator 2 can be transmitted to the wheel 3, and the torque of any power source or both power sources Whether torque is transmitted is determined based on signals and data input to the electronic control unit 38.

  On the other hand, when the vehicle Ve travels coastingly, the kinetic energy of the vehicle Ve is transmitted to the engine 1 via the transmission 7 and the power distribution device 8, and an engine braking force is generated. Further, a part of the kinetic energy transmitted to the input rotating member 29 during the repulsive traveling of the vehicle Ve is transmitted to the motor / generator 2, a regenerative braking force is generated by the motor / generator 2, and the generated electric power is stored in the power storage device. It is also possible to charge 33. This engine brake (power source brake state) can be set by increasing the gear ratio (total gear ratio) in the above-described manual mode.

  As described above, each shift stage in the transmission 7 is set based on the running state determined by the vehicle speed of the vehicle Ve, the required output (accelerator opening), and the like, and when traveling at each of these shift stages, In the power distribution device 8 corresponding to the continuously variable transmission unit, control is performed so that the rotational speed of the engine 1 becomes the optimum fuel efficiency rotational speed. Specifically, this is performed by causing the first motor / generator 14 to function as a generator or functioning as a motor to control the rotation speed. Therefore, when the rotational speed of the rotating member 29 on the input side of the transmission 7 continuously changes based on changes in the vehicle speed or the like, the rotational speed of the first motor / generator 14 is set so as to keep the engine rotational speed constant. Since it is controlled, the temperature gradually increases when the rotation speed and load are large. The control device of the present invention is configured to execute the following control in order to prevent or suppress such a situation.

  FIG. 1 is a flowchart for explaining an example of the control, and is a control example when the vehicle speed increases and the upshift is performed when the engine 1 is traveling at a constant power. First, input signal processing such as reading of necessary data is performed (step S1). Next, the temperature of the motor (MG) such as the motor / generator 14 or 2 is detected and predicted (step S2). For example, the current motor temperature is obtained, and the reached temperature of the motor is predicted from the temperature, the output of the motor, and the predicted future vehicle speed reached by the engine output at that time. Then, it is determined whether the current temperature or the predicted temperature is higher than a predetermined value set in advance as a determination criterion (step S3). The predetermined value may be a heat rated temperature determined by design for each electric motor, or may be a temperature determined in consideration of durability and efficiency.

  If a negative determination is made in step S3, a stepless speed change is executed (step S4). Here, the stepless speed change means that the engine speed before and after the speed change that changes the ratio (total speed ratio) between the engine speed and the output shaft speed (the speed of the output rotating member 30) is substantially constant. This is a mode of shifting to be maintained, and is a mode of normal shift control. Therefore, in the power distribution device 8, the rotation speed of the first motor / generator 14 is continuously changed. As a result, the rotational speed of the engine 1 connected to the carrier 13 as the input element does not change while the rotational speed of the ring gear 11 as the output element of the power distribution apparatus 8 changes. The gear ratio changes continuously (that is, steplessly).

  This will be described with reference to the drawings. FIG. 2 shows an alignment chart for the power distribution device 8 and an alignment chart for the transmission 7. In the example shown here, the transmission 7 is constituted by a planetary gear mechanism or a compound planetary gear mechanism having four rotating elements, and the first speed is set by engaging the brake B1, and the brake B2 is operated. The second speed is set by engaging. In FIG. 2, the power distribution device 8 is described as an electric CVT unit, and the transmission 7 is described as an AT unit.

  When the first speed is set by the transmission 7 by engaging the brake B1, the input rotational speed of the transmission 7 is increased, and the second speed is applied by engaging the brake B2. When the speed is set, the rotational speed of the input side member of the transmission 7 decreases. In the power distribution device 8, in order to change the output rotational speed in accordance with the rotational speed of the input side member of the transmission 7 without changing the engine rotational speed, the rotational speed of the first motor / generator 14 is negative. The rotation speed is changed to a positive rotation speed. That is, in a state where the first motor / generator 14 functions as a motor and is rotated in the reverse direction, the number of rotations is gradually reduced, and the first motor / generator 14 is further rotated forward to function as a generator. In this case, although heat is generated due to power generation, since the temperature of the first motor / generator 14 is relatively low, there is no particular problem.

  On the other hand, when the temperature of the motor is higher than the predetermined value and a positive determination is made in step S3, the shift control mode is changed from a normal continuously variable shift to a multistage shift (step S5). Here, the multi-stage shift is a shift in which the engine speed changes before and after the shift, and the change in the rotation speed of the rotating member 29 and the ring gear 11 connected to the rotary member 29 accompanying the shift in the transmission 7. On the other hand, the engine speed is changed by reducing the amount of change in the rotational speed of the sun gear 10 and the first motor / generator 14 integrated therewith or by not changing the rotational speed. In addition, such a change of the shift mode is specifically executed by changing the shift control program or changing the shift diagram.

  The multi-stage gear shifting will be described with reference to FIG. FIG. 3 is a collinear diagram similar to FIG. 2 described above. In the state where the brake B1 is engaged and the first speed is set in the transmission 7, the brake B2 is engaged and the second speed is set. An example of upshifting is shown. As described above, such a shift in the transmission 7 reduces the rotational speed of the input side member. Accordingly, when the rotational speed of the ring gear 11 that is the output member of the power distribution device 8 is decreased, the torque of the engine 1 is increased by increasing the torque without greatly changing the rotational speed of the first motor / generator 14. Reduce the speed. In other words, the rotation speed of the first motor / generator 14 in accordance with the change in the rotation speed of the output element is reduced by changing the rotation speed of the engine 1.

  Further, based on the detected temperature or the predicted temperature of the electric motor, a gear change step (a change width when changing the gear ratio stepwise) is set (step S6). For example, the higher the temperature for the electric motor, the larger the shift step is set. That is, at the gear ratio set by stopping the first motor / generator 14, power transmission by the electric path does not occur, so that the power transmission efficiency is the highest, and this state corresponds to each gear stage in the transmission 7. Occurs every time. On the other hand, the gear ratio between the gear ratios with the best power transmission efficiency is set by operating the first motor / generator 14, so that a loss associated with the electric path occurs, the power transmission efficiency decreases, and An electric motor such as the first motor / generator 14 generates heat. Such a state is most noticeable in a state where a shift occurs in the transmission 7. Therefore, when the temperature of the electric motor is high, the speed change step is increased in order to cause the speed change in the transmission 7 before the power transmission efficiency is greatly deteriorated and the heat generation amount is increased.

  The example shown in FIG. 1 is an example of upshifting, and therefore, following the above step S6, it is determined whether or not the gear ratio has become equal to or smaller than a predetermined first predetermined value α (step S7). This speed change ratio is the above-described total speed change ratio and is a ratio between the engine speed and the output shaft speed. The first predetermined value α is a determination reference value determined for each gear position of the transmission 7, and is continuously variable by operating the first motor / generator 14 from the gear ratio with the highest power transmission efficiency. This is the gear ratio that changes the gear ratio by the gear shift, and accordingly the power transmission efficiency becomes the limit of the allowable range. Therefore, if a negative determination is made in step S7, the gear ratio has not changed to such an extent that the power transmission efficiency exceeds the allowable range. Therefore, the process proceeds to the above-described step S4, and steplessly. Shifting is continued.

  On the other hand, if a negative determination is made in step S7, the engine speed is increased in accordance with the increase in vehicle speed so that the gear ratio is substantially constant (step S8). In other words, the continuously variable transmission until then is a control for changing the rotation speed of the first motor / generator 14 so that the engine rotation speed does not change, so that the output shaft rotation speed increases as the vehicle speed increases. On the other hand, a continuous speed change occurs because the engine speed does not change. In step S8, on the other hand, the first motor is controlled so that the engine speed increases according to the vehicle speed. The rotational speed of the generator 14 is controlled, and the gear ratio is maintained substantially constant accordingly. In this case, the control amount of the first motor / generator 14 is smaller than that in the case of continuously variable transmission.

  The control in step S8 is control that can be called a gear ratio fixed shift, and an example thereof is shown in a collinear diagram in FIG. FIG. 4 shows an example in which the vehicle speed increases when the first speed is set in the transmission 7. In the transmission 7, the output shaft speed increases with the brake B1 engaged. The rotational speed of the input side member gradually increases. In the shift control for maintaining the transmission ratio substantially constant, when the rotation speed of the ring gear 11 that is the output element of the power distribution device 8 is increased in accordance with the increase in the rotation speed of the input-side member of the transmission 7, The rotational speed of the motor / generator 14 is slightly changed and the rotational speed of the engine 1 is increased. As a result, the rotation speed and output of the first motor / generator 14 are reduced.

  Further, in order to keep the output of the engine 1 substantially constant (in order to achieve equal power operation), the output torque is reduced in accordance with the increase in the engine speed described above (step S9). As a result, the operating point of the engine 1 deviates from a point on the optimum fuel consumption line toward the high rotation speed and low torque side. It is determined whether or not the engine speed thus increased has reached the first reference speed, that is, whether or not the engine speed is equal to or higher than the first reference speed (step S10). The first reference rotational speed is a value at which the speed ratio after the speed change is performed by the transmission 7 becomes a predetermined second predetermined value β. The second predetermined value β can be determined in advance as a speed ratio at which the power transmission efficiency does not decrease before the speed change at the speed ratio after the speed change. Accordingly, the first reference rotational speed in step S10 can be calculated from the vehicle speed (output shaft rotational speed) and the second predetermined value β.

  If a negative determination is made in step S10, the process returns to step S8 in order to wait for the engine speed to rise. On the other hand, if an affirmative determination is made, the engine speed after the shift is the operating point at which the engine torque becomes the WOT torque (or the operating point on the lower rotational speed and higher torque side than the optimum fuel consumption line), and the transmission ratio is Shifting is performed so as to be the second predetermined value β (step S11). Here, the first predetermined value α and the second predetermined value β for the gear ratio are set to values at which the loss due to the electric motor before and after the shift is substantially equal when hysteresis is provided for the vehicle speed or the like.

  Then, the engine speed is increased in accordance with the increase in the vehicle speed so that the gear ratio becomes substantially constant (step S12). Next, it is determined whether or not the engine speed has reached the second reference speed, that is, whether or not it is equal to or higher than the second reference speed (step S13). The second reference rotational speed is a rotational speed that provides optimum fuel consumption at the engine output at that time, and is a value that schematically shows the engine operating point on the optimal fuel consumption line. If a negative determination is made in step S13, the process returns to step S12 in order to wait for an increase in the engine speed. If it is fixedly determined in the opposite direction, the first motor / generator is determined. Since there is no need to increase the rotational speed or the output of 14, the process proceeds to step S4 where a continuously variable transmission is executed. That is, the multistage shift is returned to the continuously variable shift.

  FIG. 5 is a diagram showing the relationship between the speed ratio i, which is the ratio between the engine speed and the output shaft speed, and the power transmission efficiency, with the speed ratio in the transmission 7 as a parameter. A normal case in which a continuously variable transmission is performed at a gear stage is shown, and a solid line with a thin arrow indicates an example of control by the control device according to the present invention. The transmission 7 is sequentially upshifted as the vehicle speed increases, and a stepless shift is executed by the power distribution device 8 at each shift stage. As a result, the transmission efficiency increases at each shift stage as the vehicle speed increases. However, when the electric path exceeds the maximum efficiency point of zero, the transmission efficiency gradually decreases, and then upshifted to the next shift stage. In the control device according to the present invention, since the multi-stage shift described above is executed according to the temperature of the motor, the change in transmission efficiency is improved as compared with the normal shift, and accordingly, the temperature rise of the motor is prevented, or Temperature is suppressed.

  This will be described by taking as an example an upshift from the first speed to the second speed. The speed change step of the transmission 7 is in the state of the first speed, and the stepless speed change is performed so that the engine speed is maintained at the optimum fuel consumption point, and the vehicle speed exceeds the maximum efficiency point of zero electric path. If the detected temperature or the predicted temperature of the electric motor such as the first motor / generator 14 exceeds the predetermined value in the process, the mode of the shift is changed from the stepless shift to the multi-step shift. . At the same time, the shift step is set according to the temperature. This is the control up to step S6 in FIG.

  When the speed ratio i reaches the above-mentioned first predetermined value α as the vehicle speed increases, the engine speed is increased so that the speed ratio i becomes substantially constant. Changes in engine speed and engine torque in this multi-stage shift are shown in FIGS. Since the engine 1 is operated at equal power, if the rotational speed is increased so that the gear ratio is substantially constant by multi-stage gear shifting (at time t1), the engine torque decreases as shown in FIG. Further, if the change of the operating point of the engine 1 is shown, it is as shown in FIG. 8, and the operating point that was on the optimum fuel consumption line by the stepless speed change is changed to the high rotation speed low torque side. In FIG. 8, this is indicated by a curve with arrows “t1 to t2”.

  Thus, when the engine speed reaches the first reference speed (at time t2), the gear ratio of the transmission 7 is switched stepwise from the first speed to the second speed. That is, the gear ratio i is changed so as to be the second predetermined value β. Also, the operating point of the engine 1 is changed on the isopower line to the operating point on the WOT line or the operating point on the low rotational speed high torque side (time t3). In FIG. 8, this is indicated by a curve with arrows "t2 to t3". Further, the change of the transmission gear ratio i in this process is shown by a line with a left-pointing arrow in FIG.

  Thereafter, as shown in FIGS. 6 and 7 as a change from the time point t3 to the time point t4, the engine speed is increased in accordance with the increase in the vehicle speed so that the transmission ratio i becomes substantially constant. In this process as well, the engine 1 is operating at an equal power, so the torque gradually decreases as the rotational speed increases. Accordingly, the operating point of the engine 1 moves on the equal power line indicated by the broken line in FIG. 8 from the operating point on the WOT line toward the operating point on the optimum fuel consumption line, and in FIG. 8, the arrow “t3 to t4” is attached. It is shown with a curved line. When the engine speed reaches the rotational speed at the operating point on the optimal fuel consumption line, that is, the second reference rotational speed shown in step S13 of FIG. 1, the speed change mode is switched to the stepless speed change, and the engine speed is changed to the optimal fuel efficiency. The rotational speed of the first motor / generator 14 is controlled so as to maintain the rotational speed as an operating point on the line.

  That is, in the control device according to the present invention, before the transmission gear ratio before the transmission in the transmission 7 coincides with the transmission gear ratio after the shift, the transmission in the transmission 7 is executed. 5 is a stepwise shift from the first predetermined value α to the second predetermined value β. Accordingly, the stepless speed change for operating the first motor / generator 14 is interrupted and the gear ratio of the transmission 7 is changed stepwise, so that the rotation speed and output of the first motor / generator 14 increase. Since the shift is completed before the transmission efficiency is lowered, the deterioration of the power transmission efficiency can be prevented or suppressed. In other words, since the reduction amount Dp of the output of the electric motor such as the first motor / generator 14 is greatly improved, the heat generation in each of the motor / generators 14 and 2 can be prevented or suppressed, and as a result, the durability is deteriorated. Can be suppressed. Further, according to the above control device according to the present invention, even if the gear shift in the transmission 7 is executed so that the gear ratio changes stepwise, the engine speed and torque are output in an equal output state during the gear shift process. Therefore, deterioration of drivability can be prevented or suppressed by suppressing a shift shock or a change in driving force.

  The multi-stage shift described above can be executed not only in the case of an upshift but also in the case of a downshift. It is preferable that the operating point for executing multi-stage shifting in the case of an upshift and the operating point for executing multi-stage shifting in the case of a downshift are both operating points having substantially the same power loss. In FIG. 5, α ′ indicates a point at which the multi-stage shift is executed when the transmission ratio of the transmission 7 is switched from the second speed to the first speed. By doing this, if the temperature of the motor or the predicted temperature is high, the increase in power transmission by the so-called electric path and the accompanying power loss can be reduced at the same time, regardless of whether the shift is upshift or downshift. The rise can be prevented or suppressed.

  An operating point (speed ratio i) for shifting from a multi-stage shift to a continuously variable shift is set in accordance with the fact that the operating point at which the multi-stage shift is executed at the time of upshifting and downshift is made equal to the point of power loss. The operating point (speed ratio i) for starting the automatic shift is set so as to be shifted to the higher power transmission efficiency. This is indicated by β 'in FIG. By doing so, it is possible to prevent the so-called busy shift by setting the hysteresis Hs at the shift points between the upshift and the downshift in the state where the temperature is high. Such an operating point can be set, for example, by setting the second predetermined value β shown in FIG. 1 to a value with higher power transmission efficiency than the first predetermined value α.

  In addition, changes in engine speed and engine torque during a downshift involving multi-stage shifting are schematically shown by broken lines in FIGS. 6 and 7. Therefore, in the case of a downshift, the determination in step S7 in FIG. 1 is a determination as to whether or not the gear ratio is equal to or greater than the first predetermined value α ′, and the control content in step S8 is replaced with a decrease in engine speed. Change torque reduction to torque increase. Further, the determination in step S10 is a determination as to whether or not the engine speed is equal to or lower than the first reference speed in the downshift. Is replaced with a shift to a second predetermined value β ′, and in step S12, the engine speed is decreased in accordance with the decrease in the vehicle speed. Replace with the judgment of whether or not it is below the reference speed.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means in step S2 in FIG. 1 corresponds to the temperature determining means in the present invention, and the functional means in steps S3 to S6. This corresponds to the shift mode selection means of the present invention. Furthermore, the functional means of step S4 and step S8 correspond to the prime mover control means and other prime mover control means of the present invention.

  The present invention is not limited to the specific examples described above, and the mechanism for distributing the power of the prime mover may be any mechanism that distributes the power by differential action, and may be a mechanism other than the single pinion type planetary gear mechanism. It may be configured. In addition, the transmission is not limited to a planetary gear mechanism as a main component, but includes a switching mechanism that selects a plurality of gear pairs and a gear pair that transmits torque. Any configuration can be used. Furthermore, the present invention can also be applied to a control device that targets a drive device other than a hybrid drive device.

It is a flowchart for demonstrating an example of the shift control performed with the control apparatus of this invention. It is a collinear diagram for demonstrating the behavior in the case of a continuously variable transmission. It is a collinear diagram for demonstrating the behavior at the time of multistage shifting. It is a collinear diagram for explaining the behavior when switching from a continuously variable shift to a multi-stage shift due to an increase in vehicle speed. It is a diagram which shows the relationship between the transmission gear ratio and power transmission efficiency in the case of a stepless speed change and the speed change with multistage speed change. It is a diagram which mainly shows the change of the engine speed at the time of the upshift accompanied with multistage shifting. It is a diagram which mainly shows the change of the engine torque at the time of the upshift accompanied by multistage shifting. FIG. 6 is a diagram schematically showing changes in the operating point of the engine during an upshift involving multi-stage shifting. It is a skeleton figure which shows an example of the drive device for hybrid vehicles which can be made into object by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2,14 ... Motor generator, 7 ... Transmission (stepped transmission part, AT part), 8 ... Power distribution mechanism (continuously variable transmission part, electric CVT part), 33 ... Power storage device, 38 ... Electronics Control device (control device).

Claims (12)

A continuously variable transmission that includes a power distribution mechanism that distributes the power output by the prime mover to an electric motor and an output member, and a transmission that transmits power from the output member, and that maintains the rotational speed of the prime mover substantially constant; In the control device of the driving device capable of multi-stage speed change that changes the rotational speed of the prime mover,
Temperature determining means for detecting or predicting the temperature of the electric motor;
A shift mode selection unit that selects either the stepless shift or the multi-step shift as a mode of shift to be executed based on the temperature detected or predicted by the temperature determination unit is provided. A control device for the drive device.   2. The control of a driving device according to claim 1, wherein the shift mode selection unit includes a unit that selects a multi-stage shift when the temperature detected or predicted by the temperature determination unit is higher than a determination reference value. apparatus.   The shift mode selection means includes means for selecting a multi-stage shift in which the ratio of the rotational speed of the prime mover before and after the shift increases as the temperature detected or predicted by the temperature determination means increases. The control apparatus of the drive device of Claim 1 or 2.   The multi-stage shift is performed after the ratio of the rotational speed of the prime mover and the output shaft rotational speed reaches a predetermined value by increasing the vehicle speed while the rotational speed of the prime mover is maintained at the predetermined rotational speed by the electric motor. The speed of the prime mover is increased so as to maintain the ratio at a constant value, and the speed ratio of the transmission is changed stepwise when the speed of the prime mover increases to a predetermined value. 4. The control device for a drive device according to claim 1, wherein the control device is a drive device.   The multi-stage shift is performed after the ratio of the rotational speed of the prime mover and the output shaft rotational speed reaches a predetermined value as the vehicle speed decreases while the rotational speed of the prime mover is maintained at the predetermined rotational speed by the electric motor. The speed of the prime mover is decreased so that the ratio is maintained at a constant value, and the speed ratio of the transmission is changed stepwise when the rotational speed of the prime mover decreases to a predetermined value. 5. The control device for a driving device according to claim 1, wherein the control device is a driving device.   The operating point of the prime mover after the multi-stage shift is set as an operating point at a lower rotational speed and higher torque than the optimum fuel consumption point at the output, and the ratio between the rotational speed of the prime mover and the output shaft rotational speed as the vehicle speed increases. 6. The drive apparatus control device according to claim 1, further comprising a prime mover control means for increasing the number of revolutions of the prime mover so as to be constant.   The operating point of the prime mover after the multi-stage shift is set as an operating point at a higher rotational speed and lower torque than the optimum fuel consumption point at the output, and the ratio between the rotational speed of the prime mover and the output shaft rotational speed as the vehicle speed decreases. 6. The control device for a drive device according to claim 1, further comprising another prime mover control means for reducing the number of revolutions of the prime mover so that becomes constant.   The prime mover control means executes a stepless shift that continuously changes the rotational speed of the prime mover by the motor when the power loss due to the electric motor is small when the operating point of the prime mover is changed to the optimum fuel consumption point. The drive device control device according to claim 6 or 7, further comprising:   The multi-stage shift is a shift executed at a shift point provided so that a power loss by the electric motor before an upshift is equal to a power loss by the electric motor before a downshift. The control apparatus of the drive device in any one of 1 thru | or 8.   The drive device control device according to claim 1, wherein the prime mover includes an internal combustion engine that outputs power by burning fuel.   11. The control device for a drive device according to claim 1, wherein the electric motor includes an electric motor having a power generation function.   The said drive apparatus contains the hybrid drive apparatus provided with the other electric motor which adds torque to an output torque by supplying the electric power generated with the said motor, and operate | moving. Control device for driving device.

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