JP2015147472A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably control temperature of a drive-side rotating electric machine or temperature of a cooling medium, in a hybrid vehicle.SOLUTION: A control device of a hybrid vehicle controls the hybrid vehicle which comprises: an internal combustion engine; a first rotating electric machine; a second rotating electric machine; a differential mechanism having a plurality of rotating elements which can mutually differentially rotate; power accumulation means; and a lock mechanism which maintains the differential mechanism in a locked state. The control device comprises first control means which brings the differential mechanism into the locked state when temperature of an electric apparatus is not lower than a prescribed value, and second control means which performs power regeneration amount reduction control for reducing a regeneration amount of the second rotating electric machine at gear reduction when the temperature of the electric apparatus is not lower than the prescribed value, and performs assist amount reduction control for reducing a torque assist amount generated by the second rotating electric machine according to rise of the temperature of the electric apparatus. In the case that a power accumulation residual amount of the power accumulation means is small, the control device performs the assist amount reduction control in an earlier stage more than the case that the residual amount is large.

Description

  The present invention relates to the technical field of hybrid vehicle control devices.

  A hybrid vehicle in which first and second rotating electric machines and an internal combustion engine are connected by a differential mechanism is well known. In addition, in such a vehicle configuration, a vehicle having a lock mechanism that maintains the differential mechanism in a locked state is well known. The locked state related to the differential mechanism is a state in which the ratio of the rotational speed between the drive shaft connected to the drive wheels and the internal combustion engine via the differential mechanism (that is, the gear ratio of the differential mechanism) is fixed. means.

  As a device for controlling this type of hybrid vehicle, there is a device that places the power distribution mechanism as the differential mechanism in the locked state in accordance with the temperature of a second rotating electrical machine (see Patent Document 1).

  In addition, when the load on the generator or motor is relatively large and the temperature of the electrical system including the generator or motor or the temperature of the coupling mechanism is equal to or higher than a predetermined value, the first clutch mechanism and the second clutch mechanism are simultaneously engaged. There has also been proposed one that sets a mechanical direct connection gear position (see Patent Document 2).

  Further, the output of the regenerative torque is compared with the output of the power running torque by comparing the power running torque limit that is the upper limit value of the power running torque to be output to the motor based on the temperature of the motor and the regenerative torque limit that is the upper limit value of the regenerative torque to be output to the motor. Has also been proposed (see Patent Document 3).

  Also proposed is a method in which the load limit value used for the motor generator is set to a different value when the motor generator is caused to function as a motor and when the motor generator is caused to function as a generator. (See Patent Document 4).

JP 2004-222439 A JP 2008-179356 A JP 2008-260428 A JP 2001-112101 A

  In this type of hybrid vehicle, the temperature of the drive-side rotating electrical machine responsible for torque assist for the drive shaft and power regeneration during vehicle deceleration or the temperature of the cooling medium used for cooling the drive-side rotating electrical machine is excessive. May rise. Note that this cooling medium may be used not only for cooling the rotating electrical machine on the driving side but also for cooling the rotating electrical machine on the reaction load side and the internal combustion engine.

  Here, when the differential mechanism is shifted to the locked state, the internal combustion engine and the drive shaft are directly connected to each other, and the speed ratio of the differential mechanism is fixed. Electric load can be reduced. At this time, for example, the rotating electrical machine on the reaction force load side can be shut down.

  When the load of the rotating electrical machine on the reaction force load side decreases, power transfer between the rotating electrical machine on the reaction force load side and the rotating electrical machine on the drive side can be suppressed. The load on the drive-side rotating electrical machine according to the load state of the electrical machine is also reduced. Further, when the differential mechanism is in the locked state, the absolute value of the assist torque to be supplied from the drive-side rotating electrical machine to the drive shaft is also small. Therefore, when the differential mechanism is in the locked state, the rotating electrical machine and the cooling medium on the driving side are considerably cooled. However, the cooling effect by setting the differential mechanism in the locked state does not limit the operation of the rotating electrical machine on the drive side, and therefore the cooling effect is insufficient in some cases. Therefore, conventionally, in order to obtain a larger cooling effect, it is necessary to shut down the rotating electrical machine on the driving side.

  Here, when the differential mechanism is in the locked state, it is often possible to run only with the engine torque of the internal combustion engine directly connected to the drive shaft, and even if the drive-side rotating electrical machine is shut down, the running is hindered. There may be no.

  However, if the drive-side rotating electrical machine is shut down, the drive-side rotating electrical machine cannot generate power for driving the accessory, which may affect the driving of the accessory. Further, when torque assist is requested from the drive rotating electrical machine due to a change in the traveling condition of the vehicle or the like, there is a possibility that the response of the drive rotating electrical machine is delayed and the power performance is lowered.

  That is, in the conventional apparatus, there is a possibility that problems such as a reduction in power performance and limitation of auxiliary machine driving may be manifested because sufficient temperature controllability is not ensured for the rotating electrical machine on the driving side. This invention is made in view of the situation which concerns, and makes it a subject to provide the control apparatus of the hybrid vehicle which can control the temperature of the rotary electric machine of a drive side, or a cooling medium suitably.

  In order to solve the above-described problems, a control apparatus for a hybrid vehicle according to the present invention includes a second rotating electrical machine capable of inputting and outputting torque between an internal combustion engine, a first rotating electrical machine, and a drive shaft connected to driving wheels; A plurality of first rotation elements connected to the internal combustion engine, a second rotation element connected to the first rotating electrical machine, and a third rotation element connected to the drive shaft. A differential mechanism having a rotating element; a power storage means capable of inputting and outputting power between the first and second rotating electrical machines; and a plurality of engaging elements, and the plurality of engaging elements mutually A hybrid vehicle that controls a hybrid vehicle including a lock mechanism that maintains the differential mechanism in a locked state in which a gear ratio between the internal combustion engine and the drive shaft is fixed in an engaged state. The second rotating electrical machine or the front The lock mechanism is controlled so that the plurality of engagement elements are in the engaged state when the temperature of the electrical equipment defined as the temperature of the cooling medium used for cooling the second rotating electrical machine is equal to or higher than a predetermined value. And (1) executing power regeneration amount reduction control for reducing the power regeneration amount of the second rotating electrical machine during a deceleration period of the hybrid vehicle when the temperature of the electric device is equal to or higher than a predetermined value. And (2) second control means for executing assist amount reduction control for reducing an assist amount of torque with respect to the drive shaft by the second rotating electrical machine in response to an increase in the temperature of the electric device, The second control means performs the assist amount reduction control earlier when the remaining amount of electricity stored in the electricity storage means is low than when it is high (Claim 1).

  In the hybrid vehicle according to the present invention, the first rotating electrical machine corresponds to the reaction-load-side rotating electrical machine described above, and the second rotating electrical machine corresponds to the driving-side rotating electrical machine described above.

  According to the hybrid vehicle control device of the present invention, when the electrical equipment temperature is equal to or higher than the predetermined value, the differential mechanism shifts to the locked state by the control of the lock mechanism by the first control means. When the differential mechanism shifts to the locked state, the load on the first rotating electrical machine decreases, which is effective in suppressing or increasing the temperature of the electrical equipment.

  The electrical equipment temperature according to the present invention is a temperature defined for convenience in the present invention, and the temperature of the second rotating electrical machine and at least a cooling medium (for example, cooling water) used for cooling the second rotating electrical machine. Or at least one of the temperature of the cooling oil). This cooling medium may be a cooling medium used for cooling other heat sources such as an internal combustion engine and a first rotating electric machine in a hybrid vehicle. The predetermined value used for the comparison with the electric equipment temperature may be different depending on whether the electric equipment temperature is the temperature of the second rotating electric machine or the temperature of the cooling medium.

  Note that the lock mechanism may lock the first rotating electrical machine in a non-rotatable manner by stopping the rotation of the second rotating element as long as the differential mechanism can be maintained in the locked state. The first rotating electrical machine may be substantially idle by stopping the rotation of another rotating element different from the rotating element. The substantially idle state means that the state of the differential mechanism is determined by the rotating element, the first rotating element, and the third rotating element that have stopped rotating.

  On the other hand, according to the hybrid vehicle control device of the present invention, when the electric equipment temperature is equal to or higher than the predetermined value, the second control means performs the power regeneration amount in addition to the lock control of the differential mechanism by the first control means. Reduction control and assist amount reduction control are executed. The power regeneration amount reduction control and the assist amount reduction control are controls related to suppression or promotion of increase in the temperature of the electrical equipment temperature. Henceforth, when these are comprehensively expressed, they are appropriately referred to as “overheat protection control”. Use words.

  The power regeneration amount reduction control is control for reducing a power generation load (that is, regeneration torque) during deceleration regenerative braking. Note that “reducing” means reducing compared to the case where this power regeneration amount reduction control is not executed, and is not defined by numerical limitation. When the electric power regeneration amount reduction control is executed, the regeneration torque decreases, and the temperature of the second rotating electrical machine or the cooling medium decreases.

  The assist amount reduction control is control for reducing the torque assist amount with respect to the drive shaft. Note that “reducing” means that the assist amount reduction control is reduced as compared with the case where the assist amount reduction control is not executed, and is not defined by numerical limitation. When the assist amount reduction control is executed, the assist torque supplied to the drive shaft is reduced, so that the temperature of the second rotating electrical machine or the cooling medium is lowered.

  The assist amount reduction control may be control for correcting and reducing the assist torque to a value obtained by subtracting a predetermined ratio from the originally required value. In addition, the predetermined ratio in this case may be a fixed value, or may be a variable value that is set to be larger as the degree of increase in the electric device temperature after the start time is larger.

  When the differential mechanism is in the locked state, the torque supply to the drive shaft is basically provided by the engine torque of the internal combustion engine. Generally, when the differential mechanism is locked, that is, when a fixed gear ratio is selected, the hybrid vehicle is often in a steady running state or a light load state close thereto. Therefore, generally, the torque required for the drive shaft can be covered by the engine torque. However, since the response of the engine torque is lower than the response of the torque of the rotating electrical machine, there is a possibility that a temporary torque shortage occurs during the transition period. Torque assisting by the second rotating electrical machine when the differential mechanism is in the locked state is performed, for example, to compensate for such temporary torque shortage.

  Here, the assist amount reduction control has a great influence on the acceleration performance of the vehicle, whereas the power regeneration amount reduction control replaces the regenerative braking force with a hydraulic braking force supplied from a braking device or the like. Therefore, the control has little influence on the braking performance. For this reason, in the hybrid vehicle control device according to the present invention, the power regeneration amount reduction control has priority over the assist amount reduction control.

  More specifically, the power regeneration amount reduction control is executed when the electrical equipment temperature is equal to or higher than a predetermined value, similarly to the lock control of the differential mechanism by the first control means, whereas the assist amount reduction control is performed. This is executed in response to an increase in the electrical equipment temperature during the execution period of the power regeneration amount reduction control. In short, the assist amount reduction control is started when the electrical equipment temperature reaches a value higher than a predetermined value at which execution of the power regeneration amount reduction control is started. Therefore, according to the present invention, it is possible to suitably control the electrical equipment temperature while minimizing the influence on the power performance of the hybrid vehicle.

  By the way, the remaining amount of power storage (e.g., determined by the SOC value or the like) of the power storage means for supplying power to the second rotating electrical machine is not necessarily uniquely related to the electrical equipment temperature. Therefore, when the assist amount reduction control is started without paying attention to the remaining amount of power storage, there is a possibility that the remaining amount of power storage may greatly decrease before the execution of the assist amount reduction control is started. In such a state, it becomes difficult to secure the electric power required for driving various electric drive type auxiliary machines provided in the hybrid vehicle.

  Therefore, in the control apparatus for a hybrid vehicle according to the present invention, when there is no margin in the remaining amount of electricity stored in the power storage means, the assist amount reduction control is started earlier than in the case where there is a margin. Therefore, when there is no margin in the remaining amount of power storage, it is possible to secure as much as possible the driving power of the electric drive type auxiliary machine, and it is possible to more suitably control the temperature of the electrical equipment.

  In one aspect of the control apparatus for a hybrid vehicle according to the present invention, the second control means shuts down the second rotating electrical machine when the required degree of suppression of the electric device temperature is large (Claim 2).

  The above-described overheat protection control can give high controllability to the temperature of the electric equipment, but whether the power regeneration amount reduction control or the assist amount reduction control, torque input / output in the second rotating electrical machine, that is, in the second rotating electrical machine. Power input / output is not completely stopped. Therefore, in some cases, the state where the electrical equipment temperature is excessively high may continue. Alternatively, this state may progress further.

  According to this aspect, the second rotating electrical machine is shut down when the required degree of suppression of the electrical device temperature is large. Shutdown means a state where power input / output is stopped, and means, for example, that a switching element of an inverter that drives the second rotating electrical machine is turned off. That is, the shutdown of the second rotating electrical machine is more effective than the overheat protection control in terms of the effect of lowering the temperature of the second rotating electrical machine. Therefore, according to this aspect, it is possible to more firmly suppress an increase in the electrical equipment temperature.

  The “required degree of suppression of electrical equipment temperature” refers to the degree of overheating of the second rotating electrical machine or the cooling medium obtained based on the absolute value of electrical equipment temperature, time transition, etc. qualitatively or quantitatively. It is a concept that encompasses various criteria values that can be represented.

  In this aspect, the required degree of suppression of the electric device temperature is the rate of increase of the electric device temperature, the deviation between the electric device temperature and the predetermined value, and the electric device temperature is equal to or higher than the predetermined value. The degree of request when defined by at least one of the time during which the state continues, for each of which the rate of increase is not less than a predetermined rate, the deviation is not less than a predetermined deviation, and the time is not less than a predetermined time May be determined to be large (claim 3).

  These determination reference values are suitable examples of the degree of demand for suppression of electrical equipment temperature.

  For example, when the rate of increase in electrical equipment temperature, preferably the rate of increase immediately before the electrical equipment temperature reaches a predetermined value, the temperature of the second rotating electrical machine has increased rapidly, and the degree of demand for suppression is large. It can be judged. Therefore, when the increase rate is equal to or higher than a predetermined rate that can be determined experimentally, empirically, or theoretically in advance, it can be suitably determined that the required degree of suppression of the electrical equipment temperature is large. .

  Further, when the electrical equipment temperature is greatly deviated from the predetermined value, it is determined that the electrical equipment temperature is excessively high. Therefore, when the deviation as the degree of deviation between the electric device temperature and the predetermined value is equal to or larger than a predetermined deviation that can be determined experimentally, empirically, or theoretically in advance, the required degree of suppression of the electric device temperature is It can be suitably determined that the size is large.

  In addition, when the state where the electrical equipment temperature is equal to or higher than the predetermined value continues, it is determined that the electrical equipment temperature is constantly in a high temperature state. Therefore, when the time during which the state where the electrical equipment temperature is equal to or higher than the predetermined value is longer than the predetermined time which can be determined experimentally, empirically or theoretically in advance, the request for suppression of the electrical equipment temperature is required. The determination that the degree is large can be suitably made.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

1 is a schematic configuration diagram conceptually illustrating a configuration of a hybrid vehicle according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram conceptually showing a configuration of a hybrid drive device in the hybrid vehicle of FIG. 1. FIG. 2 is an operation collinear diagram illustrating a shift mode of the hybrid vehicle in FIG. 1. It is a flowchart of MG2 overheat protection determination processing. It is a flowchart of a lock request determination process. It is a flowchart of MG1 lock execution determination processing. It is a flowchart of MG2 overheat protection processing. It is a figure explaining the control rule of each overheat protection measure in MG2 overheat protection processing. It is a flowchart of the cooling water temperature suppression determination process which concerns on 2nd Embodiment. It is a flowchart of the lock | rock request | requirement determination process which concerns on 2nd Embodiment. It is a flowchart of the MG1 lock execution determination process which concerns on 2nd Embodiment. It is a flowchart of MG2 shutdown processing concerning a 2nd embodiment. FIG. 13 is a diagram illustrating a one-hour transition of the cooling water temperature for explaining a case where the cooling water temperature suppression request is large in the process of FIG. 12.

<Embodiment of the Invention>
Various preferred embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the hybrid vehicle 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the hybrid vehicle 1.

  In FIG. 1, a hybrid vehicle 1 includes an ECU 100, a PCU (Power Control Unit) 11, a battery 12, a vehicle speed sensor 13, an accelerator opening sensor 14, an SOC sensor 15, an MG2 temperature sensor 16, a cooling water temperature sensor 17, and a hybrid drive device 10. Is an example of a “hybrid vehicle” according to the present invention.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM, and the like, and is configured to be able to control the operation of each part of the hybrid vehicle 1. It is an example of a “control device”. The ECU 100 is configured to be able to execute various processes described later according to a control program stored in the ROM.

  The ECU 100 controls the operation of a brake mechanism BR, which will be described later. The brake mechanism ECU is an example of the “first control means” according to the present invention. The engine ECU controls the operation of the engine 200, which will be described later. MG1ECU that controls the operation of the motor generator MG2, and MG2ECU that is an example of the “second control means” according to the present invention that controls the operation of the motor generator MG2 to be described later. However, in the present embodiment, for the purpose of preventing the explanation from becoming complicated, the description of these components is omitted, and all the operations will be described as the operation of the ECU 100. In addition, it is possible to have a configuration in which one ECU 100 actually controls the operation of the hybrid vehicle 1.

  The PCU 11 converts the DC power extracted from the battery 12 into AC power and supplies it to a motor generator MG1 and a motor generator MG2, which will be described later, and also converts AC power generated by the motor generator MG1 and the motor generator MG2 into DC power. Including an inverter (not shown) configured to be supplied to the battery 12, and the power input / output between the battery 12 and each motor generator or the power input / output between the motor generators (ie, in this case, This is a control unit configured to be able to control power transfer between the motor generators without passing through the battery 12. The PCU 11 is electrically connected to the ECU 100, and its operation is controlled by the ECU 100. The inverter in the PCU 11 includes an MG1 driving inverter that drives the motor generator MG1 and an MG2 driving inverter that drives the motor generator MG2.

  The battery 12 is a rechargeable power storage unit that functions as a power supply source related to power for powering the motor generator MG1 and the motor generator MG2. The battery 12 has a configuration in which unit secondary battery cells having an output voltage of V are connected in series in units of several hundreds.

  The vehicle speed sensor 13 is a sensor configured to be able to detect the vehicle speed SPD of the hybrid vehicle 1. The vehicle speed sensor 13 is electrically connected to the ECU 100, and the detected vehicle speed SPD is appropriately referred to by the ECU 100.

  The accelerator opening sensor 14 is a sensor configured to be able to detect an accelerator opening Ta, which is an operation amount of an accelerator pedal (not shown) of the hybrid vehicle 1. The accelerator opening sensor 14 is electrically connected to the ECU 100, and the detected accelerator opening Ta is referred to the ECU 100 as appropriate.

  The SOC sensor 15 is a sensor configured to be able to detect an SOC value Soc representing the SOC (State Of Charge) of the battery 12. The SOC sensor 15 is electrically connected to the ECU 100, and the detected SOC value Soc is referred to the ECU 100 as appropriate.

  The SOC value Soc is a standardized value corresponding to the remaining amount of electricity stored in the battery 12, and 0 (%) indicating that the remaining amount of electricity stored in the battery 12 is zero (that is, a fully discharged state). ) To 100 (%) indicating that the battery 12 is fully charged. In the hybrid vehicle 1, the SOC value Soc is maintained in a range not less than the system lower limit value Socll (0 <Socll) and less than the system upper limit value Socul (Socul <100) by known SOC control.

  MG2 temperature sensor 16 is a sensor configured to be able to detect MG2 temperature Thrm, which is the temperature of motor generator MG2. The MG2 temperature sensor 16 is electrically connected to the ECU 100, and the detected MG2 temperature Thrm is referred to the ECU 100 as appropriate.

  The MG2 temperature Thm is an example of the “electric device temperature” according to the present invention, but the “electric device temperature” according to the present invention may be, for example, the temperature of the MG2 driving inverter.

  The cooling water temperature sensor 17 is a sensor configured to be able to detect the cooling water temperature Thw that is the temperature of the system cooling water of the hybrid vehicle 1. The coolant temperature sensor 17 is electrically connected to the ECU 100, and the detected coolant temperature Thw is referred to the ECU 100 as appropriate.

  The system cooling water is an example of the “cooling medium” according to the present invention that cools each part that can become a heat source in the operation process of the hybrid vehicle 1, such as the engine 200, the PCU 11, the battery 12, the motor generator MG1, and the motor generator MG2. It is. That is, the cooling water temperature Thw is an example of the “electric equipment temperature” according to the present invention.

  The system cooling water is circulated and supplied to each part of the hybrid vehicle 1 by a known cooling water circulation supply device (not shown) including, for example, an electric water pump and various electromagnetically operated switching valves. Here, the system cooling water is circulated and supplied to all of the cooling targets. However, the system cooling water may be separately circulated and supplied by the engine 200 and other electrical devices, for example. In this case, the cooling water circulated and supplied to other electrical equipment can be handled as the “cooling medium” according to the present invention.

  In addition, although illustration is abbreviate | omitted for the purpose of preventing complication of drawing, the well-known various sensor which concerns on the state detection of the hybrid vehicle 1 is mounted in the hybrid vehicle 1 besides illustration. For example, a sensor (for example, a crank position sensor or an intake air sensor) related to the state detection of the engine 200, a sensor (for example, an inverter temperature sensor) related to the state detection of the PCU 11, and various operations operated by the driver are included therein. A sensor (for example, a brake pedal sensor, a shift switch sensor, or the like) related to the operation state detection of the means is included.

  The hybrid drive device 10 is a power train of the hybrid vehicle 1. The hybrid drive device 10 is configured to be able to transmit power supplied from an engine 200 and motor generators MG1 and MG2, which will be described later, to an axle VS connected to the drive wheels DW.

  Here, the detailed configuration of the hybrid drive apparatus 10 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram conceptually showing the configuration of the hybrid drive apparatus 10. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  In FIG. 2, the hybrid drive device 10 includes an engine 200, a power split mechanism 300, a motor generator MG1, a motor generator MG2, a brake mechanism BR, and a speed reduction mechanism 400.

  The engine 200 is a gasoline engine that is an example of an “internal combustion engine” according to the present invention, and is configured to function as a power source of the hybrid vehicle 1. The “internal combustion engine” in the present invention is a concept that encompasses an engine that can extract thermal energy associated with fuel combustion by converting it into kinetic energy. As long as the concept is satisfied, the configuration of the internal combustion engine according to the present invention is not limited to that of the engine 200 and may have various aspects.

  The engine torque Te, which is the output power of the engine 200 via a crankshaft (not shown), is input to the input shaft IS of the hybrid drive device 10.

  Returning to FIG. 2, motor generator MG <b> 1 is a motor generator that is an example of a “first rotating electrical machine” according to the present invention, and has a power running function that converts electrical energy into kinetic energy, and a regeneration that converts kinetic energy into electrical energy. It has a configuration with functions.

  The motor generator MG2 is a motor generator that is an example of a “second rotating electrical machine” according to the present invention. Like the motor generator MG1, the motor generator MG2 converts a power running function that converts electrical energy into kinetic energy, and converts kinetic energy into electrical energy. It has a configuration with a regenerative function.

  Motor generators MG1 and MG2 are configured as, for example, synchronous motor generators, and include, for example, a rotor having a plurality of permanent magnets on an outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field. It has become. However, these may have other configurations.

  The power split mechanism 300 includes a sun gear S1 as an example of the “second rotating element” according to the present invention provided in the center, and a “third rotation” according to the present invention provided concentrically on the outer periphery of the sun gear S1. The ring gear R1, which is an example of the “element”, the plurality of pinion gears P that are arranged between the sun gear S1 and the ring gear R1 and revolve while rotating on the outer periphery of the sun gear S1, and the rotation shafts of these pinion gears are supported. This is a planetary gear mechanism as an example of a “differential mechanism” according to the present invention, which includes a planetary carrier C1 as an example of a “first rotating element” according to the present invention.

  Sun gear S1 is coupled to motor generator MG1 via sun gear shaft SS, and the rotational speed thereof is equivalent to MG1 rotational speed Nmg1, which is the rotational speed of motor generator MG1.

  The ring gear R1 is connected to the drive shaft DS, and the drive shaft DS is connected to the axle VS via the speed reduction mechanism 400. The reduction mechanism 400 is a gear mechanism including various reduction gears including a differential gear and the like.

  That is, in the hybrid drive device 10, the drive shaft rotational speed Nd, which is the rotational speed of the drive shaft DS, takes a value that is unambiguous with respect to the vehicle speed. Further, since motor generator MG2 is also connected to drive shaft DS, drive shaft rotation speed Nd and rotation speed of ring gear R1 are equivalent to MG2 rotation speed Nmg2, which is the rotation speed of motor generator MG2. In other words, the MG2 rotational speed Nmg2 naturally takes a value unique to the vehicle speed.

  Although the motor generator MG2 is directly connected to the drive shaft DS here, a transmission or a speed reduction device may be appropriately interposed between the drive shaft DS and the motor generator MG2.

  The planetary carrier C1 is connected to the input shaft IS described above. Therefore, the rotational speed of the planetary carrier C1 is equivalent to the engine rotational speed Ne of the engine 200.

  Under such a configuration, the power split mechanism 300 transmits the engine torque Te, which is the output power of the engine 200, to the sun gear S1 and the ring gear R1 through the planetary carrier C1 and the pinion gear P1 (a ratio between each gear). (The ratio according to the gear ratio).

  At this time, in order to make the operation of the power split mechanism 300 easy to understand, if the gear ratio ρ as the number of teeth of the sun gear S1 with respect to the number of teeth of the ring gear R1 is defined, the engine torque Te is applied from the engine 200 to the planetary carrier C1. In this case, the torque Tes acting on the sun gear S1 can be expressed by the following formula (1), and the direct torque Tep appearing on the drive shaft DS can be expressed by the following formula (2).

Tes = Te × ρ / (1 + ρ) (1)
Tep = Te × 1 / (1 + ρ) (2)
The brake mechanism BR is an engagement device that is an example of the “locking unit” according to the present invention, and includes a plurality of engagement elements, and the plurality of engagement elements are configured to be able to engage or separate from each other. One engaging element of the brake mechanism BR is fixed to a fixing element such as a chassis, for example, and the other engaging element is fixed to the sun gear S1. Therefore, when the brake mechanism BR is in an engaged state in which a plurality of engaging elements are engaged with each other, the sun generator S1 and the motor generator MG1 coupled to the sun gear S1 are maintained in a non-rotatable locked state. On the other hand, when the brake mechanism BR is in a non-engagement state in which a plurality of engagement elements are separated from each other, the sun gear S1 and the motor generator MG1 connected to the sun gear S1 are maintained in a rotatable unlocked state. .

  The physical configuration of the brake mechanism BR is not limited at all. For example, the brake mechanism BR can take the form of a known hydraulic control type wet multi-plate brake device, dog clutch device, cam lock device, or the like. In any case, the brake mechanism BR is configured such that a drive device that drives the engagement element is electrically connected to the ECU 100, and the operation state is controlled by the ECU 100.

<Operation of Embodiment>
<Details of shift mode>
The shift mode of the hybrid vehicle 1 according to the present embodiment is controlled to either the fixed shift mode or the continuously variable shift mode according to the operating state of the brake mechanism BR.

  Here, the shift mode of the hybrid vehicle 1 will be described with reference to FIG. Here, FIG. 3 is an operation collinear diagram of the hybrid drive device 10. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof will be omitted as appropriate.

  FIG. 3A is a collinear diagram corresponding to the continuously variable transmission mode. The vertical axis represents the rotational speed.

  The power split mechanism 300 is a two-degree-of-freedom differential mechanism constructed by three rotating elements having a differential relationship with each other, and includes a sun gear S1 (uniquely motor generator MG1) and a carrier C1 (uniquely). When the rotational speeds of two elements of the engine 200) and the ring gear R1 (uniquely the motor generator MG2) are determined, the rotational speed of the remaining one rotational element is inevitably determined. That is, on the operation collinear diagram, the operation state of each rotary element can be represented by one operation collinear line corresponding to one operation state of the hybrid drive device 10 on a one-to-one basis.

  For example, in FIG. 3A, it is assumed that the operating point of the motor generator MG2 that is uniquely related to the vehicle speed is the operating point m1. In this case, if the operating point of motor generator MG1 is operating point g1, the operating point of engine 200 connected to carrier C1, which is the remaining rotating element, is operating point e1.

  Here, for convenience, assuming that the rotational speed of the ring gear R1 is constant, when the operating point of the motor generator MG1 is changed to the operating point g2 and the operating point g3, the operating point of the engine 200 is the operating point. e2 and operating point e3. That is, in power split device 300, engine speed Ne of engine 200 can be freely changed by using motor generator MG1 as a rotational speed control device. The speed change mode corresponding to this state is the continuously variable speed change mode. In the continuously variable transmission mode, the operating point of the engine 200 (the operating point in this case means one operating condition of the engine 200 defined by the combination of the engine rotational speed Ne and the engine torque Te) basically. The fuel consumption rate of the engine 200 is controlled to the optimum fuel consumption operating point at which the fuel consumption rate is substantially minimized.

  Here, in the continuously variable transmission mode, of course, the MG1 rotational speed Nmg1 needs to be variable. Therefore, when the continuously variable transmission mode is selected, the operation state of the brake mechanism BR is controlled so that the sun gear S1 is in the unlocked state. That is, the engagement elements of the brake mechanism BR are maintained in a state of being separated from each other.

  In order to supply the direct torque Tep described above to the drive shaft DS in the power split mechanism 300, a reaction force torque having the same magnitude as the above-described torque Tes appearing in the sun gear SS according to the engine torque Te and having the sign reversed is used. It is necessary to supply from the motor generator MG1. In this case, at the operating point in the positive rotation region such as the operating point g1 or the operating point g2, MG1 is in a power regeneration state (that is, a power generation state) of positive rotation negative torque. As described above, in the continuously variable transmission mode, the motor generator MG1 functions as a reaction force element, so that the direct drive torque Tep as a part of the engine torque Te is supplied to the drive shaft DS and distributed to the sun gear shaft SS. Power generation using the torque Tes can be performed. When the direct torque Tep supplied to the drive shaft DS is insufficient with respect to the required torque, the MG2 torque Tmg2 that is the output torque of the motor generator MG2 is supplied to the drive shaft DS, and torque assist is appropriately performed.

  On the other hand, for example, when traveling at a high speed and a light load, the MG1 rotational speed Nmg1 may be a value in the negative rotational region corresponding to the operating point g3, for example. Since motor generator MG1 outputs a negative torque as a reaction torque of engine torque Te, in this case, MG1 enters a state of negative rotation negative torque and enters a power running state. That is, in this case, MG1 torque Tmg1 that is the output torque of motor generator MG1 is transmitted to drive shaft DS as the drive torque of hybrid vehicle 1.

  Therefore, motor generator MG2 enters a power regeneration state of positive and negative torque to absorb excessive torque output to drive shaft DS. In this state, MG1 torque Tmg1 is used for power regeneration in motor generator MG2, and motor generator MG1 is driven by this regenerative power, resulting in an inefficient electrical path called power circulation. Become. In a state where the power circulation occurs, the energy efficiency of the hybrid vehicle 1 decreases.

  Therefore, in the hybrid vehicle 1, the MG1 lock request flag RqLk is set to ON in advance in an operation region where such power circulation can occur, and the sun gear S1 is controlled to be locked by the control of the brake mechanism BR under the control of the ECU 100. .

  FIG. 3B shows the state. When the sun gear S1 shifts to the locked state by the brake mechanism BR, the sun gear S1 becomes unable to rotate, and the operating point of the motor generator MG1 is fixed to the illustrated operating point g0.

  In this case, the remaining engine rotational speed Ne is uniquely determined by the MG1 rotational speed Nmg1 (Nmg1 = 0) and the vehicle speed and the unique MG2 rotational speed Nmg2 (see e0 in the drawing). That is, when the motor generator MG1 is in the locked state, the gear ratio, which is the ratio between the engine rotational speed Ne, the vehicle speed SPD, the MG2 rotational speed Nmg2, and the drive shaft rotational speed Nd is constant. The shift mode corresponding to this locked state is the fixed shift mode.

  In the fixed speed change mode, a reaction force torque that opposes the torque Tes can be borne through the brake mechanism BR. Therefore, motor generator MG1 can be shut down. Therefore, electrical loss in the hybrid drive device 10 is reduced, and energy efficiency is improved.

  In the fixed speed change mode, the system required output Psys that is a required output of the hybrid vehicle 1 is basically covered by the engine output Pe that is the output of the engine 200. However, unlike motor generator MG1 that cannot physically rotate, the operation of motor generator MG2 is not limited even in the fixed speed change mode.

  Therefore, in practice, when the response of the direct torque Tep supplied to the drive shaft DS is delayed with respect to the change in the required drive force according to the accelerator operation, the torque of the drive shaft DS is transiently insufficient. The torque assist is appropriately performed by the MG2 torque Tmg2. For this reason, the driving force responsiveness of the hybrid vehicle 1 is ensured even in the fixed speed change mode. Further, when the hybrid vehicle 1 is decelerated, regenerative torque is output from the motor generator MG2, and regenerative braking is performed using this regenerative torque. The generated electric power obtained by regenerative braking is used as electric power for charging the battery 12 or electric power for driving auxiliary equipment for driving various electric driving auxiliary equipment. In addition to the regenerative braking at the time of deceleration, the motor generator MG2 appropriately generates, for example, auxiliary driving power, etc. during normal driving as well. In this case, since a part of the engine direct torque Tep is used for power generation, the engine direct torque Tep is added to the driving shaft required torque required for the driving shaft DS as a driving force by an amount corresponding to this power generation load. Is done.

  Note that the system required output Psys is, for example, a drive required output determined by selecting values corresponding to the accelerator opening degree Ta and the vehicle speed SPD from a request output map stored in advance in the ROM, and the SOC of the battery 12. It is determined by appropriately correcting the auxiliary machine required power generation amount determined based on the value Soc, the charge limit value Win, the discharge limit value Wout, the auxiliary machine power consumption, and the like. Various known methods can be applied as a method for calculating the system required output Psys.

<Details of MG2 overheat protection control>
In hybrid vehicle 1, MG2 overheat protection control for preventing an excessive temperature rise of motor generator MG2 is performed by ECU 100. The MG2 overheat protection control includes an MG2 overheat protection determination process, a lock request determination process, an MG1 lock execution determination process, and an MG2 overheat protection process.

  First, the details of the MG2 overheat protection determination process will be described with reference to FIG. FIG. 4 is a flowchart of the MG2 overheat protection determination process.

  In FIG. 4, ECU 100 obtains MG2 temperature Thm (step S110). When the MG2 temperature Thm is acquired, it is determined whether or not the acquired MG2 temperature Thm is equal to or higher than the overheat protection determination value Thmot (step S120).

  When MG2 temperature Thm is equal to or higher than overheat protection determination value Thmot (step S120: YES), overheat protection request flag RqRdThm indicating whether motor generator MG2 is in an overheat state indicates that motor generator MG2 is in an overheat state. Is set to “ON” (step S130). When the overheat protection request flag RqRdThm is set to ON, the MG2 overheat protection determination process ends, and the process returns to step S110 again after a predetermined interval.

  On the other hand, when the MG2 temperature Thm is less than the overheat protection determination value Thmot (step S120: NO), whether or not the MG2 temperature Thm is equal to or less than the return determination value obtained by subtracting the hysteresis set value Thmots from the overheat protection determination value Thmot. Is determined (step S140). If the MG2 temperature Thm is higher than the return determination value (step S140: NO), the MG2 overheat protection determination process ends for the purpose of preventing hunting, and the process returns to step S110 again after a predetermined interval.

  When MG2 temperature Thm is equal to or lower than the return determination value (step S140: YES), overheat protection request flag RqRdThm is set to “OFF” indicating that motor generator MG2 is not in an overheated state. When the overheat protection request flag RqRdThm is set to OFF, the MG2 overheat protection determination process ends, and the process returns to step S110 again after a predetermined interval.

  The MG2 overheat protection determination process is executed as described above.

  Next, details of the lock request determination process will be described with reference to FIG. FIG. 5 is a flowchart of the lock request determination process.

  In FIG. 5, ECU 100 determines whether or not there is a request for MG2 overheat protection (step S210). Specifically, it is determined whether or not the overheat protection request flag RqRdThm is “ON”.

  When there is an MG2 overheat protection request (step S210: YES), that is, when the overheat protection request flag RqRdThm is set to ON, an MG1 lock request flag RqLkRdThm indicating whether or not MG1 lock for overheat protection is necessary. Is set to “ON” indicating that MG1 lock for overheating protection of motor generator MG2 is necessary (step S220). When the MG1 lock request flag RqLkRdThm is set to ON, the lock request determination process ends, and the process returns to step S210 again after a predetermined interval.

  On the other hand, when there is no MG2 overheat protection request (step S210: NO), that is, when the overheat protection request flag RqRdThm is set to OFF, the MG1 lock request flag RqLkRdThm is MG1 locked for overheat protection of the motor generator MG2. Is set to “OFF” indicating that it is unnecessary (step S230). When the MG1 lock request flag RqLkRdThm is set to OFF, the lock request determination process ends, and the process returns to step S210 again after a predetermined interval.

  The lock request determination process is executed as described above.

  Next, the details of the MG1 lock execution determination process will be described with reference to FIG. FIG. 6 is a flowchart of the MG1 lock execution determination process.

  First, the ECU 100 determines whether or not there is an MG1 lock request (step S310). Specifically, the MG1 lock request flag RqLkRdThm for MG2 overheat protection described above, or the MG1 lock request flag RqLk due to other requirements (for example, the fuel efficiency improvement request by preventing the occurrence of power circulation, etc.). It is determined whether or not is set to ON.

  If there is an MG1 lock request (step S310: YES), it is further determined whether or not MG1 lock is prohibited (step S320). Specifically, it is determined whether or not the MG1 lock prohibition flag IhLk indicating whether or not MG1 lock is prohibited is “OFF” indicating that MG1 lock is not prohibited.

  The MG1 lock prohibition flag IhLk is set to “ON” indicating that the MG1 lock is prohibited when a preset MG1 lock prohibition condition is satisfied, and the MG1 lock is prohibited when the lock prohibition condition is not satisfied. It is set to “OFF” indicating that it is not performed. The lock prohibition condition is, for example, when the drive shaft required torque is equal to or higher than the upper limit value of the direct torque Tep of the engine 200 in the MG1 locked state, when the vehicle speed Spd is less than the MG1 lock lower limit vehicle speed, or This is established when the temperature of is higher than a predetermined value.

  If MG1 locking is not prohibited (step S320: YES), ECU 100 controls brake mechanism BR to lock motor generator MG1 (step S330). Step S330 is an example of the operation of the “first control means” according to the present invention.

  The state where motor generator MG1 is locked is equivalent to the state where power split device 300 has shifted to the “locked state” according to the present invention. When motor generator MG1 shifts to the locked state, MG1 lock flag ExLk indicating whether MG1 lock is being executed is set to “ON” indicating that MG1 lock is being executed.

  On the other hand, when MG1 lock is prohibited (step S320: NO), or when there is no MG1 lock request in step S310 (step S310: NO), ECU 100 unlocks motor generator MG1 (step S340). . If the motor generator MG1 is already in the unlocked state at this time, substantially nothing is performed. When the locked state of motor generator MG1 is released, MG1 lock flag ExLk indicating whether MG1 lock is being executed is set to “OFF” indicating that MG1 lock is not being executed.

  When step S330 or S340 is executed, the process returns to step S310 again after a predetermined interval. The MG1 lock execution determination process is executed as described above.

  Next, the details of the MG2 overheat protection process will be described with reference to FIG. FIG. 7 is a flowchart of the MG2 overheat protection process.

  In FIG. 7, ECU 100 acquires MG2 temperature Thm and SOC value Soc of battery 12 (step S410).

  Next, ECU 100 determines whether or not there is a margin in the SOC of battery 12 (step S420). Specifically, in step S420, it is determined whether or not the acquired SOC value Soc is equal to or greater than the determination reference value Socct. The determination reference value Socct is larger than the above-described system lower limit value Socll, and the SOC value Soc does not violate the system lower limit value Socll in the course of the change in advance experimentally, empirically or theoretically. Thus, it determines according to the degree of the effect of the various overheat protection measures mentioned later.

  When the SOC of battery 12 has a margin (step S420: YES), that is, when SOC value Soc is greater than or equal to determination reference value Socct, ECU 100 executes a first overheat protection process related to MG2 overheat protection (step S430). ). On the other hand, when the SOC of battery 12 has no margin (step S420: NO), that is, when SOC value Soc is less than determination reference value Socct, ECU 100 executes the second overheat protection process related to MG2 overheat protection ( Step S440). When step S430 or S440 is executed, the MG2 overheat protection process ends, and the process returns to step S410 again after a predetermined interval. The MG2 overheat protection process is executed as described above.

  The execution of the first and second overheat protection processes is an example of the operation of the “second control means” according to the present invention.

  Next, the details of the first and second overheat protection processes will be described with reference to FIG. FIG. 8 is a diagram for explaining the control rules of the respective overheat protection measures in the first and second overheat protection processes.

  FIG. 8 illustrates the execution timing of the overheat protection measures of the first overheat protection process (upper stage) and the second overheat protection process (lower stage) for the MG2 temperature Thm.

  The first overheat protection process is composed of P1 to P4 overheat protection measures, and the second overheat protection measure is composed of P1, P2 and P4 overheat protection measures.

  In both the first overheat protection process and the second overheat protection process, the overheat protection measure P1 is executed when the MG2 temperature Thm reaches the overheat protection determination value Thmot.

  The overheat protection measure P1 is a measure for reducing the deceleration regeneration amount of the motor generator MG2, and is an example of the “power regeneration amount reduction control” according to the present invention. In the overheat protection measure P1, regenerative braking at the time of vehicle deceleration is replaced with the braking force of the braking device provided in the hybrid vehicle 1. Although the ratio of this replacement is not particularly limited, in the overheat protection measure P1, for example, as a preferred embodiment, the power generation load for driving the auxiliary machinery and the power generation load corresponding to the electrical and mechanical loss of the hybrid drive device 10 are used. Except for, power regeneration during deceleration is stopped.

  In both the first overheat protection process and the second overheat protection process, the overheat protection measure P4 is executed when the MG2 temperature Thm reaches the allowable upper limit value Thm4 (Thmot <Thm4 <Thmmax). Thmmax is an absolute allowable upper limit value derived from a physical standard (for example, an operation guarantee temperature range) of motor generator MG2.

  Overheat protection measure P4 is a measure for shutting down motor generator MG2. The shutdown means that each switching element of the MG2 driving inverter in the PCU 11 is deenergized to stop its operation. The overheat protection measure P4 is the measure with the highest overheat protection effect of the motor generator MG2 because the generation of heat in the motor generator MG2 is stopped.

  In the first overheat protection process, after the overheat protection measure P1 is executed, when the MG2 temperature Thm further rises and reaches Thm2 (Thmot <Thm2 <Thm4), the execution of the overheat protection measure P2 is started. The overheat protection measure P1 is continued as it is.

  The overheat protection measure P2 is a measure for limiting torque assist for the drive shaft DS by the motor generator MG2, and is an example of “assist amount reduction control” according to the present invention. In a state where motor generator MG1 is locked, hybrid vehicle 1 basically runs only with engine direct torque Tep as described above. At this time, torque assist by the motor generator MG2 is performed for the purpose of compensating for a response delay during acceleration. In the overheat protection measure P2, the assist torque related to this torque assist is reduced. Note that the degree of reduction is not particularly limited. For example, the assist torque that is originally required may be corrected to the decrease side by a constant or indefinite correction coefficient. Alternatively, the degree of reduction may be increased as the MG2 temperature Thm increases.

  In the first overheat protection process, after the overheat protection measure P2 is executed, when the MG2 temperature Thm further rises and reaches Thm3 (Thmo2 <Thm3 <Thm4), the execution of the overheat protection measure P3 is started. The overheat protection measures P1 and P2 are continued as they are.

  The overheat protection measure P3 is a measure to reduce the power generation load corresponding to the power for driving the auxiliary machinery and the power corresponding to the electrical and mechanical loss in the hybrid drive device 10. When the temperature rise of the motor generator MG2 does not stop even with the overheat protection measure P3 and reaches the above-described allowable upper limit value Thm4, the above-described overheat protection measure P4 is started. In the first overheat protection process, each overheat protection measure is executed in accordance with such a control rule.

  On the other hand, in the second overheat protection process, after the overheat protection measure P1 is executed at the overheat protection judgment value Thmot, the MG2 temperature Thm rises and reaches Thm1 (Thmot <Thm1 <Thm2). Execution starts. Thereafter, the overheat protection measure P2 continues until the MG2 temperature Thm reaches the allowable upper limit value Thm4. The overheat protection measure P1 is continued as it is.

  Thus, in the second overheat protection process, the overheat protection measure P2 is activated earlier than the first overheat protection process. This is due to the fact that there is no room in the remaining amount of electricity stored in the battery 12. That is, when switching of the control rule according to the remaining amount of power stored in the battery 12 is not executed, the SOC value Soc is lowered to the vicinity of the above-described system lower limit value Socll before the overheat protection measure P2 is activated with the MG2 temperature Thm as a control requirement. However, there is a possibility that the power for driving auxiliary equipment and the power for loss compensation are insufficient. Since there is no correlation between the MG2 temperature Thm and the remaining amount of electricity stored in the battery 12, the occurrence of this kind of situation has conventionally been overlooked.

  On the other hand, according to the overheat protection control performed in the hybrid vehicle 1, particularly the MG2 overheat protection process, the control rule of each overheat protection measure is switched in accordance with the remaining amount of power stored in the battery 12 (here, the SOC value Soc). It is done. Therefore, it is possible to suppress the increase in the MG2 temperature Thm or to promote the decrease in the MG2 temperature Thm while suitably maintaining the state of the battery 12.

  In addition, according to the overheat protection control, in particular, MG2 overheat protection processing, various overheat protection measures for urging the temperature of motor generator MG2 are executed step by step in combination according to a predetermined control rule. Therefore, the heat generation of motor generator MG2 can be controlled in stages, and good controllability is imparted to MG2 temperature Thm.

  Further, as described above, the overheat protection measure P2 is a measure that may cause a decrease in the power performance of the hybrid vehicle 1, whereas the overheat protection measure P1 is basically a measure that can be replaced by the braking force of the braking device. It is. In view of this point, both the first and second overheat protection processes are configured such that the overheat protection measure P1 has priority over the overheat protection measure P2. In other words, the configuration is such that the heat generation of motor generator MG2 can be controlled in stages while suppressing a decrease in the running performance of hybrid vehicle 1. As a result, it is possible to suppress the deterioration of the running performance of the hybrid vehicle 1 as much as possible while protecting the motor generator MG2 from overheating.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the second embodiment, overheating of the system cooling water of the hybrid vehicle 1 is suppressed by the cooling water temperature overheat protection control executed by the ECU 100. The vehicle configuration according to the second embodiment is the same as that of the first embodiment.

<Details of cooling water temperature overheat protection control>
The cooling water temperature overheat protection control includes a cooling water temperature suppression determination process, a lock request determination process, an MG1 lock execution determination process, and an MG2 shutdown process.

  First, details of the cooling water temperature suppression determination process will be described with reference to FIG. FIG. 9 is a flowchart of the cooling water temperature suppression determination process.

  In FIG. 9, the ECU 100 acquires the coolant temperature Thw (step S510). When the coolant temperature Thw is acquired, it is determined whether or not the acquired coolant temperature Thw is equal to or higher than the suppression determination value Thmow (step S520).

  When the coolant temperature Thw is equal to or higher than the suppression determination value Thmow (step S520: YES), the coolant temperature suppression request flag RqRdThw indicating whether or not the system coolant is in an overheated state indicates that the system coolant is in an overheated state. Is set to “ON” (step S530). When the coolant temperature suppression request flag RqRdThw is set to ON, the coolant temperature suppression determination process ends, and the process returns to step S510 again after a predetermined interval.

  On the other hand, when the cooling water temperature Thw is lower than the suppression determination value Thwow (step S520: NO), it is further determined whether or not the cooling water temperature Thw is equal to or less than the return determination value obtained by subtracting the hysteresis setting value Thwoths from the suppression determination value Thwot. A determination is made (step S540). If the cooling water temperature Thw is higher than the return determination value (step S540: NO), the cooling water temperature suppression determination process is terminated for the purpose of preventing hunting, and the process returns to step S510 again after a predetermined interval.

  When the cooling water temperature Thw is equal to or lower than the return determination value (step S540: YES), the cooling water temperature suppression request flag RqRdThw is set to “OFF” indicating that the system cooling water is not overheated. When the cooling water temperature suppression request flag RqRdThw is set to OFF, the cooling water temperature suppression determination process ends, and the process returns to step S510 again after a predetermined interval.

  The cooling water temperature suppression determination process is executed as described above.

  Next, details of the lock request determination process will be described with reference to FIG. FIG. 10 is a flowchart of the lock request determination process.

  In FIG. 10, the ECU 100 determines whether or not there is a request for cooling water temperature suppression (step S610). Specifically, it is determined whether or not the cooling water temperature suppression request flag RqRdThw is “ON”.

  When there is a cooling water temperature suppression request (step S610: YES), that is, when the cooling water temperature suppression request flag RqRdThw is set to ON, an MG1 lock request indicating whether or not MG1 lock for cooling water temperature suppression is necessary The flag RqLkRdThw is set to “ON” indicating that the MG1 lock for cooling water temperature suppression is necessary (step S620). When the MG1 lock request flag RqLkRdThw is set to ON, the lock request determination process ends, and the process returns to step S610 again after a predetermined interval.

  On the other hand, when there is no cooling water temperature suppression request (step S610: NO), that is, when the cooling water temperature suppression request flag RqRdThw is set to OFF, the MG1 lock request flag RqLkRdThw does not require MG1 lock for cooling water temperature suppression. Is set to “OFF” to indicate that it is (step S630). When the MG1 lock request flag RqLkRdThw is set to OFF, the lock request determination process ends, and the process returns to step S610 again after a predetermined interval.

  The lock request determination process is executed as described above.

  Next, the details of the MG1 lock execution determination process will be described with reference to FIG. FIG. 11 is a flowchart of the MG1 lock execution determination process.

  First, the ECU 100 determines whether or not there is an MG1 lock request (step S710). Specifically, the MG1 lock request flag RqLkRdThw for suppressing the cooling water temperature described above, or the MG1 lock request flag RqLk due to other requirements (for example, the fuel efficiency improvement request by preventing the occurrence of power circulation). It is determined whether or not is set to ON.

  If there is an MG1 lock request (step S710: YES), it is further determined whether or not MG1 lock is prohibited (step S720). Specifically, it is determined whether or not the MG1 lock prohibition flag IhLk indicating whether or not MG1 lock is prohibited is “OFF” indicating that MG1 lock is not prohibited. Note that the MG1 lock prohibition flag IhLk is the same as that in the first embodiment, and a description thereof will be omitted here.

  If MG1 locking is not prohibited (step S720: YES), ECU 100 controls brake mechanism BR to lock motor generator MG1 (step S730). Step S730 is an example of the operation of the “first control means” according to the present invention. When motor generator MG1 shifts to the locked state, MG1 lock flag ExLk indicating whether MG1 lock is being executed is set to “ON” indicating that MG1 lock is being executed.

  On the other hand, when MG1 lock is prohibited (step S720: NO), or when there is no MG1 lock request in step S710 (step S710: NO), ECU 100 unlocks motor generator MG1 (step S740). . If the motor generator MG1 is already in the unlocked state at this time, substantially nothing is performed. When the locked state of motor generator MG1 is released, MG1 lock flag ExLk indicating whether MG1 lock is being executed is set to “OFF” indicating that MG1 lock is not being executed.

  When step S730 or S740 is executed, the process returns to step S710 again after a predetermined interval. The MG1 lock execution determination process is executed as described above.

  Next, the details of the MG2 shutdown process will be described with reference to FIG. FIG. 12 is a flowchart of the MG2 shutdown process.

  In FIG. 12, ECU 100 determines whether or not the coolant temperature suppression request is large (step S810). When the coolant temperature suppression request is large (step S810: YES), ECU 100 shuts down motor generator MG2 (step S820).

  When motor generator MG2 is shut down or when it is determined in step S810 that the cooling water temperature suppression request is not large (step S810: NO), MG2 shutdown processing is terminated, and the processing is again stepped through a predetermined interval. It returns to S810. The MG2 shutdown process is executed as described above.

  Here, with reference to FIG. 13, the case where the cooling water temperature suppression request | requirement is large is demonstrated. FIG. 13 is a diagram exemplifying a one-hour transition of the cooling water temperature Thw for explaining a case where the cooling water temperature suppression request is large.

  In FIG. 13, the time transition of the cooling water temperature Thw is illustrated in the upper stage, and the time transition of the cooling water temperature suppression request flag RqRdThw is illustrated in the lower stage.

  Here, it is assumed that the cooling water temperature Thw shows the transition indicated by the upper solid line in the figure. In this case, the cooling water temperature suppression request flag RqRdThw is set ON at time t1 when the cooling water temperature Thw reaches the above-described suppression determination value Thwot, and the cooling water temperature Thw decreases to the return determination value ThWot ′ corresponding to the above-described return determination value. At time t3.

  Here, in particular, FIG. 13 shows three types of (1) to (3) quantitative indicators of the cooling water temperature suppression request.

  (1) in the figure is the value of the inclination (inclination of the arrow in the figure) of the cooling water temperature Thw immediately before the cooling water temperature suppression request flag RqRdThw is set to ON. When this value is equal to or greater than a judgment value (that is, an example of the “predetermined rate” according to the present invention) determined experimentally, empirically or theoretically in advance, the cooling water temperature suppression request is large. Is made. That is, when this inclination is large, the cooling water temperature Thw is considered to increase rapidly even after the cooling water temperature Thw reaches the suppression determination value Thwot, so that it can be determined that the cooling water temperature suppression request is large.

  The illustration (2) is a deviation between the cooling water temperature Thw and the suppression determination value Thwot. When this value is equal to or greater than a determination value (that is, an example of the “predetermined deviation” according to the present invention) determined experimentally, empirically, or theoretically in advance, the cooling water temperature suppression request is large. Is made. That is, when this deviation is large, it is considered that the system cooling water is in an overheated state, and therefore it can be determined that the cooling water temperature suppression request is large. The case where it is determined that the cooling water temperature suppression request is large due to the requirement (2) is equivalent to the case where the MG2 temperature Thm reaches the allowable upper limit value Thm4 in the first embodiment.

  The figure (3) is the length of the period when the cooling water temperature suppression request flag RqRdThw is set to ON. When this value is greater than or equal to a judgment value (that is, an example of the “predetermined time” according to the present invention) determined experimentally, empirically or theoretically in advance, the cooling water temperature suppression request is large. Is made. That is, when the period during which the flag is set on is long, the system cooling water is considered to be constantly overheated, so that it can be determined that the cooling water temperature suppression request is large.

  According to the present embodiment, when the cooling water temperature suppression request is large in a state where the motor generator MG1 is locked, the motor generator MG2 is shut down. Therefore, overheating can be suitably suppressed in the system cooling water of the hybrid vehicle 1.

  Although description is omitted in the second embodiment, in the first embodiment, the switching of the control rule of the overheat protection measure according to the SOC of the battery 12 described with reference to FIG. The same applies to the form.

  On the other hand, in the determination of whether or not the cooling water temperature suppression request is large described with reference to FIG. 13 in the second embodiment, the cooling water temperature Thw is replaced with the MG2 temperature Thm, and the motor generator MG2 according to the first embodiment. It can also be used to suppress overheating. In this case, the overheat protection measure P4 related to the shutdown of the motor generator MG2 is activated also by requirements other than the requirements by the MG2 temperature Thm illustrated in FIG. 8, and better temperature control of the motor generator MG2 can be realized.

  In the first and second embodiments, the power split mechanism 300 is exemplified as the differential mechanism according to the present invention, but the mode of the differential mechanism is not limited to this. Further, the rotating element that is to be locked by the brake mechanism BR can also change according to the mode of the differential mechanism.

  For example, as an example of the differential mechanism according to the present invention, a composite differential mechanism in which one differential mechanism corresponding to the power split mechanism 300 and another differential mechanism are connected can be constructed. At this time, two rotating elements in each differential mechanism may be connected to each other so that the composite differential mechanism as a whole has four rotating elements. For example, the ring gear R1 of the power split mechanism 300 is connected to the carrier of another differential mechanism, and the carrier C1 is connected to the ring gear. These, the sun gear S1, and the sun gear of the other differential mechanism are 4 in number. Individual rotating elements may be realized.

  Even in such a configuration, the composite differential mechanism as a whole is a differential mechanism with two degrees of rotation. If the sun gear of another differential mechanism is locked by a brake mechanism, the rotational speed of the sun gear ( The engine rotation speed Ne is uniquely determined by the zero rotation) and the vehicle speed Spd. That is, the gear ratio is fixed. In this case, although the motor generator MG1 is not locked, the degree of freedom of rotation is lost, and the reaction force torque against the torque Tes is borne by the brake mechanism, so the motor generator MG1 can be shut down. The MG2 overheat protection control and the cooling water temperature suppression control described above can also be applied to such a vehicle configuration.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and control of a hybrid vehicle involving such a change. The apparatus is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Hybrid vehicle, 10 ... Hybrid drive device. DESCRIPTION OF SYMBOLS 100 ... ECU, 200 ... Engine, 300 ... Power split mechanism, MG1 ... Motor generator, MG2 ... Motor generator, BR ... Brake mechanism.

Claims (3)

An internal combustion engine;
A first rotating electrical machine;
A second rotating electrical machine capable of inputting / outputting torque to / from a drive shaft connected to the drive wheel;
A plurality of rotations capable of differentially rotating with each other, including a first rotating element connected to the internal combustion engine, a second rotating element connected to the first rotating electrical machine, and a third rotating element connected to the drive shaft A differential mechanism with elements;
Power storage means capable of inputting and outputting electric power between the first and second rotating electrical machines;
A gear ratio between the internal combustion engine and the drive shaft is fixed when the differential mechanism has an engagement state in which the plurality of engagement elements are engaged with each other. A hybrid vehicle control device that controls a hybrid vehicle including a lock mechanism that maintains a locked state,
The plurality of engaging elements are in the engaged state when an electrical device temperature defined as a temperature of the second rotating electrical machine or a cooling medium used for cooling the second rotating electrical machine is equal to or higher than a predetermined value. First control means for controlling the lock mechanism,
When the electrical equipment temperature is equal to or higher than a predetermined value, (1) executing power regeneration amount reduction control for reducing the power regeneration amount of the second rotating electrical machine during the deceleration period of the hybrid vehicle, and (2) And second control means for executing assist amount reduction control for reducing an assist amount of torque with respect to the drive shaft by the second rotating electrical machine in response to a rise in electrical equipment temperature,
The control device for a hybrid vehicle, wherein the second control means executes the assist amount reduction control earlier when the remaining amount of electricity stored in the electricity storage means is low than when it is high. 2. The control apparatus for a hybrid vehicle according to claim 1, wherein the second control unit shuts down the second rotating electrical machine when a degree of request for suppression of the electric device temperature is large. The degree of demand for suppression of the electrical device temperature is such that the rate of increase in the electrical device temperature, the deviation between the electrical device temperature and the predetermined value, and the state where the electrical device temperature is equal to or higher than the predetermined value. It is defined by at least one of the times, and for each, when the rate of increase is equal to or greater than a predetermined rate, the deviation is equal to or greater than a predetermined deviation, and the time is equal to or greater than a predetermined time, it is determined that the required degree is large. The control apparatus for a hybrid vehicle according to claim 2.

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