JP2012224203A - Hybrid vehicle drive control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly switch a speed change mode from a fixed gear ratio mode into a continuously variable transmission mode without increasing motor physique.SOLUTION: A hybrid vehicle drive control device includes: a boundary value determination means for determining a boundary value of output torque of a drive shaft; a range determination means for determining a range of the output torque of an internal combustion engine, which is capable of maintaining the output torque of the drive shaft to requested torque corresponding to requested drive force, based on the determined boundary value; a fixing means for fixing the engine output torque to a torque value within the determined range in a process that the engine output torque changes according to the change of the requested torque with the requested drive force changed; a compensation control means for compensating a difference between the requested torque and the fixed engine output torque by input/output of power; and a switch control means for switching the speed change mode while the engine output torque is fixed and the difference is compensated.

Description

  The present invention relates to a technical field of a drive control device for a hybrid vehicle that controls a hybrid vehicle that can switch a shift mode between a fixed gear ratio mode and a continuously variable transmission mode.

  As a technical idea related to this type of device, for example, Patent Document 1 discloses that the engine torque is kept constant and only the motor drive state is changed when switching from the fixed gear ratio mode to the continuously variable transmission mode. It is disclosed that the releasing means is released after the braking torque of the releasing means is made zero, and then the engine and the motor are coordinated.

  In Patent Document 2, in a hybrid vehicle having a fixed gear ratio mode and a continuously variable transmission mode, the required driving force can be provided when the required driving force can be covered by MG2 during traveling in the fixed gear ratio mode. Is disclosed by MG2, and the technical idea of switching the fixed gear ratio mode to the continuously variable transmission mode when the required driving force cannot be covered by MG2 is disclosed.

  Patent Document 3 discloses that in a hybrid vehicle having a fixed gear ratio mode and a continuously variable transmission mode, when the continuously variable transmission mode is switched to the fixed gear ratio mode, the engine torque is kept constant and the required driving force is excessive or insufficient. The technical idea of outputting the minutes by a motor is disclosed.

  Further, in Patent Document 4, in a hybrid vehicle having a fixed gear ratio mode and a continuously variable transmission mode, the engine torque is increased during the fixed gear ratio mode to change to an efficient operating point, and the torque corresponding to that is changed to MG2. The technical idea of generating electricity is disclosed.

JP 2007-050776 A JP 2009-132190 A JP 2010-274735 A JP 2009-132186 A

  In the device disclosed in Patent Document 1, since the engine torque is kept constant, the torque of the motor required to satisfy the driver's required driving force changes according to the driver's required driving force. become. The driver's required driving force has various time change rates and absolute values, and an increase in the motor size is unavoidable in order to cope with any case. An increase in the motor size is not preferable from the viewpoint of installation space and cost.

  On the other hand, if the size of the motor is limited in consideration of the installation space and cost, the required operation of the motor will inevitably exceed the compensable range of the motor when the required driving force change of the driver is large. Thus, the output torque of the drive shaft becomes discontinuous under conditions exceeding the compensation range, and a relatively large physical impact that can be perceived by the driver may reduce comfort.

  Such a problem can also occur in the devices disclosed in Patent Document 2 and Patent Document 3. In particular, in the device disclosed in Patent Document 2, since the motor is used up to the operating limit before the fixed gear ratio mode is switched to the continuously variable transmission mode, the engine torque is fixed during the shift mode switching process. I can not. For this reason, the release processing of the clutch device and the brake device must be performed in a state where the engine torque is changing, and in particular, in a rotation synchronous meshing engagement device such as a dog clutch, between a pair of engagement elements. It becomes difficult to control the reaction force element for mitigating or canceling the physical impact called so-called rattling.

  On the other hand, since the technical idea disclosed in Patent Document 4 is not applied at the time of switching the shift mode, the above-described problem that occurs at the time of switching the shift mode cannot be solved.

  That is, in the various conventional techniques described above, when switching the fixed gear ratio mode to the continuously variable transmission mode, there are costs and installation problems due to an increase in the size of the motor, and an engagement device for realizing the switching of the transmission mode. There is a technical problem that it is difficult to simultaneously solve both the comfort problem caused by the smooth release control of the vehicle.

  The present invention has been made in view of the above-described technical problems, and is a hybrid vehicle that can smoothly shift the shift mode from the fixed gear ratio mode to the continuously variable transmission mode without increasing the motor size. It is an object to provide a drive control device.

  In order to solve the above-described problems, a drive control apparatus for a hybrid vehicle according to the present invention is connected to an internal combustion engine, a first rotating electrical machine, a first rotating element connected to the first rotating electrical machine, and the internal combustion engine. Between the drive shaft and a power transmission mechanism including a plurality of rotary elements having a differential action with each other, including a second rotary element and a third rotary element connected to a drive shaft connected to the axle. A second rotating electrical machine capable of input / output; and a pair of engaging elements, one of which is connected to one of the rotating elements in the power transmission mechanism and the other is connected to a fixed element. When in the disengaged state, a stepless speed change mode capable of continuously changing the rotational speed of the internal combustion engine with respect to the rotational speed of the drive shaft is realized as the speed change mode of the power transmission mechanism, The engaging element is engaged Between the first and second rotating electrical machines and the engagement device that realizes the fixed gear ratio mode in which the rotational speed of the internal combustion engine and the rotational speed of the drive shaft are uniquely related to each other. A hybrid vehicle drive control device for controlling a hybrid vehicle comprising a power storage means capable of input / output of the vehicle, wherein the fixed gear ratio mode is changed to the continuously variable transmission mode in accordance with a change in the driver's required driving force. Boundary value determining means for determining a boundary value of the output torque of the drive shaft that can be compensated by input / output of electric power between the second rotating electrical machine and the power storage means when the shift mode switching request is generated. And a range of the output torque of the internal combustion engine capable of maintaining the output torque of the drive shaft at the required torque corresponding to the required drive force based on the determined boundary value. In a process in which the output torque of the internal combustion engine changes with the change of the required torque accompanying the change of the required drive force with the range determining means, the output torque of the internal combustion engine is set at a torque value within the determined range. Fixing means for fixing, compensation control means for compensating the difference between the required torque and the output torque of the fixed internal combustion engine by the input and output of the electric power, and the output torque of the internal combustion engine is fixed and the difference is compensated And switching control means for switching the speed change mode from the fixed speed ratio mode to the continuously variable speed change mode (Claim 1).

  A hybrid vehicle drive control device according to the present invention is a device for controlling a hybrid vehicle according to the present invention. As a preferred embodiment, for example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units) ), A single or a plurality of ECUs (Electronic Controlled Units), computer systems, and the like that include various processors or various controllers. In addition, various storage means such as a ROM (Read Only Memory), a RAM (Random Access Memory), a buffer memory, or a flash memory can be appropriately attached to these.

  The hybrid vehicle according to the present invention has physical and mechanical characteristics such as fuel type, fuel supply mode, fuel combustion mode, intake / exhaust system configuration, and cylinder arrangement as power elements capable of supplying torque to the drive shaft. Alternatively, an internal combustion engine as an engine capable of generating power by burning fuel and various motor generators capable of powering and power generation (that is, power regeneration), which can take various modes regardless of electrical configuration, etc. First and second rotating electrical machines. In addition, the hybrid vehicle according to the present invention is provided between the internal combustion engine as the power element and the first and second rotating electric machines and the drive shaft directly connected to the axle or indirectly connected through various gear mechanisms. The power transmission mechanism which enables torque transmission is provided.

  The power transmission mechanism includes at least a first rotating element connected to the first rotating electrical machine, a second rotating element connected to the internal combustion engine, and a third rotating element connected to the drive shaft. It is preferably configured as a differential mechanism with two degrees of freedom of rotation, which includes a plurality of rotating elements that act. The number of rotating elements or differential mechanisms provided in the power transmission mechanism is ambiguous, and the power transmission mechanism may include one or a plurality of various differential gear mechanisms such as a planetary gear mechanism. In the case of including a plurality of planetary gear mechanisms, a part of the rotating element constituting each planetary gear mechanism may be shared as appropriate between the plurality of planetary gear mechanisms.

  In view of the differential action between the rotating elements in the power transmission mechanism, the first rotating element connected to the first rotating electrical machine functions as a reaction force element that applies a reaction torque to the internal combustion engine. As for the torque of the internal combustion engine input to the power transmission mechanism via the second rotation element, a part of the direct torque corresponding to this reaction torque is transmitted to the drive shaft via the third rotation element. In such a configuration, the first rotating electrical machine continuously causes a speed ratio, which is a ratio between the engine rotational speed of the internal combustion engine and the rotational speed of the drive shaft (unique to the rotational speed of the axle), at least within a predetermined range. Can be variable. That is, the power transmission mechanism and the first rotating electrical machine preferably function as a kind of electric CVT (Continuously Variable Transmission). The speed change mode of the power transmission mechanism in which this kind of electric CVT state is realized is appropriately referred to as “continuously variable speed mode” in the present invention. In the continuously variable transmission mode, a relatively high degree of freedom is given to the operating point of the internal combustion engine by the rotation control by the first rotating electrical machine and the torque control of the internal combustion engine. Using this point, the operating point of the internal combustion engine in the continuously variable transmission mode is, as a preferred embodiment, the efficiency of the entire hybrid vehicle (for example, the thermal efficiency of the internal combustion engine, the charge / discharge efficiency between the rotating electrical machine and the power storage means, It may be controlled to the optimum fuel consumption operating point at which the power transmission mechanism (related to the torque transmission efficiency by the torque dividing action, etc.) becomes the maximum.

  On the other hand, the second rotating electrical machine is configured to be able to input / output torque to / from the drive shaft directly connected to the drive shaft or indirectly connected through various gear mechanisms, engagement mechanisms, and the like. The second rotating electrical machine uses the input torque in the positive rotation region, for example, when torque is input through a power transmission path that sequentially passes through the driving wheel, the axle, and the driving shaft (that is, negative torque). Power regeneration is possible, and it is possible to bear at least part of the drive shaft torque as the output torque of the drive shaft by supplying positive torque (ie, powering) to the drive shaft in the positive rotation region, for example. It is. The hybrid vehicle according to the present invention absorbs or assists the second rotating electrical machine as needed to absorb the excess or deficiency of the above-mentioned direct torque with respect to the drive shaft required torque required for the drive shaft by the driver's accelerator operation or the like. While driving.

  The hybrid vehicle according to the present invention includes an engagement device that can adopt various rotation-synchronized engagement mechanisms such as a dog clutch mechanism as a preferred embodiment. The engagement device includes a pair of engagement elements. In the released state in which the pair of engagement elements are released from each other, the above-described continuously variable transmission mode can be realized as the transmission mode of the power transmission mechanism. it can. On the other hand, one of the pair of engagement elements is connected to a fixed element (that is, a brake element), and the other is connected to one rotation element of the power transmission mechanism, and these are engaged with each other. The rotation of the one rotation element can be fixed at zero rotation. The power transmission mechanism is configured such that the above-described gear ratio is uniquely determined when the engagement device adopts this engagement state.

  In view of the operation of fixing the gear ratio, the other engagement element of the engagement device is not connected to at least the second and third rotation elements. For example, when the other engagement element of the pair of engagement elements is connected to the first rotation element, when the engagement device is in the engagement state, the rotation of the first rotating electrical machine is forced to zero rotation, The engine rotation speed of the internal combustion engine is uniquely fixed by the rotation of the drive shaft affected by the rotation of the axle and the above-described differential action (in the case where a physical transmission is provided) The gear ratio can be ambiguous in the range of the gear ratio that can be adopted by the gear stage of the transmission, but the engine speed and the rotational speed of the drive shaft are unambiguous for one gear stage). Such a state may be referred to as, for example, “MG1 lock”. Further, depending on the configuration of the power transmission mechanism, it is possible to maintain the first rotation element in a fixed rotation state and fix the gear ratio without directly preventing the rotation of the first rotation element. For example, the power transmission mechanism includes a plurality of differential mechanisms, and a plurality of rotating elements in one differential mechanism are coupled to a plurality of rotating elements in the other differential mechanism, respectively. In the case of being configured as a differential mechanism, the gear ratio can be similarly fixed if the first and second rotating electric machines and the remaining one-rotation element not connected to the internal combustion engine are prevented from rotating.

  Incidentally, when the fixed gear ratio mode is selected by the engagement device, a physical reaction force can be applied to the internal combustion engine from the engagement device. Therefore, in the fixed gear ratio mode, it is not necessary to apply the reaction force by the first rotating electrical machine, and from the viewpoint of avoiding unnecessary power consumption, the first rotating electrical machine is preferably not used in the fixed gear ratio mode. Maintained in operation.

  On the other hand, a request for switching the shift mode from the fixed gear ratio mode to the continuously variable transmission mode can be ambiguous. As an example, the driving force requested by the driver through the accelerator pedal operation (driver requested driving force) This type of switching request can also occur if it increases or decreases. When the fixed gear ratio mode is switched to the continuously variable transmission mode in the process of changing the driver required driving force, the discontinuity of the driving shaft torque before and after the switching and the physical impact generated between the pair of engaging elements in the engaging device. Since it is necessary to avoid the resulting torque shock or the like, it is necessary to accurately control the reaction force torque applied from the first rotating electrical machine.

  In particular, in a rotation-synchronized meshing device in which a gap called play (gap) is generated between a pair of engaging elements, such as a dog clutch, a rattling noise or rattling during reaction force torque transfer is generated. To alleviate the shock, the need is even greater. This is because in this type of device, the pair of engagement elements cannot be shifted to the released state when torque is applied between the pair of engagement elements. This is because the torque acting between them needs to be maintained at or near zero torque. For example, if the controllability of the reaction torque of the first rotating electrical machine is low, the state of the pair of engagement elements frequently switches between the torque acting state and the torque non-acting state, and each time the rattling sound is generated. And rattling shocks, etc., can result in significantly reduced comfort.

  The drive control apparatus for a hybrid vehicle according to the present invention solves this problem by the action of the boundary value determining means, the range determining means, the fixing means, the compensation control means, and the switching control means.

  In other words, according to the hybrid vehicle drive control device of the present invention, the boundary value determination is performed when a request for switching the transmission mode from the fixed transmission ratio mode to the continuously variable transmission mode occurs in response to a change in the required driving force of the driver. The boundary value of the drive shaft torque is determined by the means. Here, the boundary value of the drive shaft torque is the input / output of power between the second rotating electrical machine and the power storage means (note that the input of power means power regeneration by the second rotating electrical machine, Means the limit value of the value of the drive shaft torque that can be adjusted by the second rotating electrical machine), and the output torque of the internal combustion engine described later When the drive shaft torque becomes excessive with respect to the drive shaft required torque due to the fixing measure, the limit value of the torque on the regeneration side is conversely. On the contrary, when the drive shaft torque is insufficient with respect to the drive shaft required torque, the power running side It means the limit value of torque.

  The limit value is not limited to the value corresponding to the specification or rated operation limit established based on physical or electrical constraints, but various control laws applied at that time, or at that time. It may be a value corresponding to an operation limit that can be appropriately determined in terms of control based on various constraints that may occur.

  On the other hand, when such a boundary value is determined, the range of the output torque of the internal combustion engine that can maintain the drive shaft torque at the drive shaft required torque is determined based on the determined boundary value. . “The range is determined” is a concept including the determination of an upper limit value or the like that can substantially define the range. In short, the range of the output torque is a torque range that is less than a predetermined torque threshold in the process in which the required driving force decreases (that is, the driving shaft required torque also decreases), and the required driving In the process in which the force increases (that is, the drive shaft required torque also increases), the torque range is greater than a certain torque threshold.

  When the range of the output torque of the internal combustion engine is determined by the range determining means, the output torque of the internal combustion engine is fixed within the range of the output torque by the fixing means. Further, the divergence between the drive shaft torque and the required drive shaft torque that may occur after the fixed time of the output torque is compensated by power regeneration or torque assist that is realized by the compensation control means. . By such compensation control of the drive shaft torque by the compensation control means, the drive shaft torque is maintained at the drive shaft required torque without any problem on the surface.

  In this way, the switching control means is such that the drive shaft torque matches the drive shaft required torque by the compensation control of the drive shaft torque, and the output torque of the internal combustion engine by the fixing means is a value within the previously determined range (ideal Is an upper limit value of the determined range (hereinafter, this value is appropriately expressed as “fixed torque threshold value” etc.), and the engagement device is controlled to control a pair of engagements. The shift mode is switched from the fixed gear ratio mode to the continuously variable transmission mode by shifting the combination element to the released state.

  Here, the drive control device for a hybrid vehicle according to the present invention mainly has two characteristic technical ideas. The first is that the output torque of the internal combustion engine is fixed, and the second is that the target value for fixing the output torque of the internal combustion engine takes into account the state of the power storage means and the second rotating electrical machine at that time. Is to be determined.

  According to the first characteristic technical idea, since the output torque of the internal combustion engine is fixed, the controllability required for controlling the reaction torque of the first rotating electrical machine described above can be relatively low. This is apparent in view of the fact that the controllability of an internal combustion engine that requires a fuel combustion process for torque output is clearly inferior to the controllability of a first rotating electrical machine driven by power control such as PWM. If the required controllability is relatively low, the difficulty of maintaining the pair of engagement elements in the torque non-actuated state is alleviated, and the engagement device can be smoothly and quickly moved to the released state. Can do it.

  By the way, when it is necessary to end the fixed gear ratio mode according to the driver's required driving force, if no measures are taken in order to enjoy the benefits of fixing the output torque of the internal combustion engine in this way, Since the driver-requested driving force linked to the driving operation cannot be predicted in advance, the input / output torque required for the second rotating electrical machine may exceed the operation limit of the second rotating electrical machine. When such a phenomenon occurs, the drive shaft torque becomes discontinuous, and thus torque fluctuation of the drive shaft torque may significantly reduce comfort. In view of this point, it is necessary to increase the physique of the second rotating electrical machine in advance to the extent that it can withstand the occurrence of this type of phenomenon. As a result, there are disadvantages in terms of cost and vehicle mountability.

  The second characteristic technical idea takes this point into account, and in order to enjoy the practical benefits of the first characteristic technical idea, the fixed value of the output torque of the internal combustion engine, the power storage means, and the second A correlation is established with the state of the rotating electrical machine. The effect of having such a correlation appears as a point at which the timing for fixing the output torque of the internal combustion engine to the fixed torque threshold is variable in actual control. That is, the present invention is essence in that a fixed torque threshold value (uniquely torque fixing timing) that matches the physique of the second rotating electrical machine is set, not giving the physique of the second rotating electrical machine, By setting such a fixed torque threshold value, it is possible to realize a smooth and quick switching of the shift mode without incurring a disadvantage in terms of cost and vehicle mountability.

  In one aspect of the drive control apparatus for a hybrid vehicle according to the present invention, the engagement device is formed in a rotation synchronization state in which the pair of engagement elements are synchronized with each other and in the rotation direction. A rotation-synchronized engagement device that is in the engaged state in a loosely packed state (claim 2).

  According to this aspect, the engagement device requires the rotation synchronization process and the backlash process as the engagement process, and the torque control process toward the torque non-operation state as the release process. It is configured as a type of engagement device. Therefore, the effect of the present invention that the pair of engaging elements are smoothly and quickly shifted to the released state is most noticeable.

  In another aspect of the drive control apparatus for a hybrid vehicle according to the present invention, the boundary value determination means is smaller as the change amount of the required drive force is larger, and the target charge / discharge amount of the power storage means is smaller. The boundary value is determined so as to become smaller (Claim 3).

  According to this aspect, since the boundary value of the drive shaft torque can be accurately associated with the states of the second rotating electrical machine and the power storage means, the margin required from the safety aspect can be further increased for the physique of the second rotating electrical machine. This can be reduced, and is further advantageous in terms of cost and vehicle mountability.

  The target charge / discharge amount of the power storage means is, for example, a charge / discharge amount allowable value of the power storage means (for example, a so-called Win (charge limit value) or Wout (discharge limit value)), and the current value of the second rotating electrical machine at that time. The value obtained by converting the rotation speed into electric power, and the output torque of the second rotating electrical machine at that time and the maximum torque as an absolute value (considering the sign of positive and negative, the minimum torque during charging and the maximum during discharging) Torque) or the like. At this time, a map or the like in which these parameter elements are associated with the target charge / discharge amount may be prepared, or these parameters may be prepared according to a calculation rule or the like that has been established experimentally, empirically, or theoretically in advance. From the above, the target charge / discharge amount may be derived as appropriate.

  In another aspect of the drive control apparatus for a hybrid vehicle according to the present invention, the first force that applies a reaction force to the internal combustion engine within a period from when the switching request is generated until the output torque of the internal combustion engine is fixed. Maintenance control means for maintaining the output torque of the rotating electrical machine at a value corresponding to less than the output torque of the internal combustion engine corresponding to the required driving force is further provided.

  According to this aspect, during the period until the output torque of the internal combustion engine is fixed to the fixed torque value by the fixing means, the output torque of the internal combustion engine (where the output torque of the first rotating electrical machine corresponds to the required drive shaft torque) In the fixed gear ratio mode, since the drive shaft torque is typically covered by the output torque of the internal combustion engine, this torque corresponds to less than (which can also be interpreted as coincident with the required drive shaft torque). Maintained at the value.

  That is, the essential point of this aspect is that the release operation of the engagement device is started substantially after the output torque of the internal combustion engine is fixed to the fixed torque threshold value. In this way, in the process in which the output torque of the internal combustion engine reaches the fixed torque threshold, the balance between the reaction force torque applied from the first rotating electrical machine and the output torque of the internal combustion engine is lost, and an unnecessary rattling sound is generated. The possibility of occurrence of rattling shock or torque shock is remarkably reduced, which is extremely beneficial from the viewpoint of ensuring comfort.

  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. 3 is an operation alignment chart illustrating one operation state of the hybrid drive device of FIG. 2. 2 is a timing chart for explaining an operation state of the hybrid vehicle in FIG. 1 when switching from a fixed gear ratio mode to a continuously variable transmission mode. 2 is a timing chart for explaining an operating state of the hybrid vehicle in FIG. 1 when switching from a fixed gear ratio mode to a continuously variable transmission mode. 2 is a flowchart of a switching control process executed by an ECU in the hybrid vehicle of FIG. It is a conceptual diagram of the charge side boundary value map referred in the switching control process of FIG. It is a conceptual diagram of the discharge side boundary value map referred in the switching control process of FIG. FIG. 7 is a timing chart illustrating one operating characteristic of the hybrid vehicle of FIG. 1 corresponding to the case where the target charge amount is large when the required driving force is reduced, according to the effect of the switching control process of FIG. 6. FIG. 7 is a timing chart illustrating one operating characteristic of the hybrid vehicle of FIG. 1 corresponding to the case where the target charge amount is small when the required driving force is increased, according to the effect of the switching control process of FIG. 6. It is a flowchart of the switching control process which concerns on 2nd Embodiment of this invention. FIG. 12 is a timing chart illustrating one operating characteristic of the hybrid vehicle of FIG. 1 when the required driving force is reduced, according to the effect of the switching control process of FIG. 11. It is a flowchart of the switching control process which concerns on 3rd Embodiment of this invention. FIG. 10 is a timing chart illustrating one operating characteristic of the hybrid vehicle in FIG. 1 when the required driving force is reduced, according to the effect of the fourth embodiment of the present invention.

<Embodiment of the Invention>
Embodiments of the present invention will be described below with reference to the drawings.

<Configuration of Embodiment>
First, with reference to FIG. 1, the structure of the hybrid vehicle 1 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the hybrid vehicle 1.

  In FIG. 1, the hybrid vehicle 1 includes an ECU 100, a PCU (Power Control Unit) 11, a battery 12, an accelerator position sensor 13, a vehicle speed sensor 14, and a hybrid drive device 10 according to the present invention. It is.

  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. 1 is an example of a “drive control device for a hybrid vehicle”. The ECU 100 is configured to be able to execute a switching control process described later according to a control program stored in the ROM.

  The ECU 100 functions as an example of each of “boundary value determining means”, “range determining means”, “fixing means”, “compensation control means”, “switching control means”, and “maintenance control means” according to the present invention. The electronic control unit is configured as described above, and all the operations related to these means are configured to be executed by the ECU 100. However, the physical, mechanical, and electrical configurations of each of the units according to the present invention are not limited to this. For example, each of these units includes a plurality of ECUs, various processing units, various controllers, a microcomputer device, and the like. It may be configured as various computer systems.

  The hybrid drive device 10 drives the hybrid vehicle 1 by supplying driving torque as driving force to the left axle SFL (corresponding to the left front wheel FL) and the right axle SFR (corresponding to the right front wheel FR), which are the axles of the hybrid vehicle 1. Drive unit. The detailed configuration of the hybrid drive device 10 will be described later.

  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 battery 12 has a configuration in which a plurality (for example, several hundreds) of unit battery cells such as lithium ion battery cells are connected in series, and a power supply source related to power for powering the motor generator MG1 and the motor generator MG2. Is an example of the “power storage means” according to the present invention. The battery 12 also functions as a supply destination of the regenerative power when the power of the motor generator MG1 and the motor generator MG2 is regenerated. That is, the battery 12 is a rechargeable secondary battery.

  The accelerator opening sensor 13 is a sensor configured to be able to detect an accelerator opening Ta as an operation amount of an accelerator pedal (not shown) of the hybrid vehicle 1. The accelerator opening sensor 13 is electrically connected to the ECU 100, and the detected accelerator opening Ta is referred to by the ECU 100 at a constant or indefinite period.

  The vehicle speed sensor 14 is a sensor configured to be able to detect the vehicle speed V of the hybrid vehicle 1. The vehicle speed sensor 14 is electrically connected to the ECU 100, and the detected vehicle speed V is referred to by the ECU 100 at a constant or indefinite period.

  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 assigned to the same parts as those in FIG.

  In FIG. 2, the hybrid drive apparatus 10 includes an engine 200, a power split mechanism 300, a motor generator MG1 (hereinafter appropriately referred to as “MG1”), a motor generator MG2 (hereinafter appropriately referred to as “MG2”), an MG2 deceleration. A mechanism 400, a drive shaft 500, a speed reduction mechanism 600, a brake mechanism 700, and an MG2 output shaft 800 are provided.

  The engine 200 is a gasoline engine that is an example of an “internal combustion engine” according to the present invention that is configured to function as a main power source of the hybrid vehicle 1. The engine 200 is a known gasoline engine, and a detailed configuration thereof is omitted here, but the engine torque Te that is the output power of the engine 200 is input to the power split mechanism 300 via a crankshaft (not shown). It is configured to be transmitted to the shaft 310. The engine 200 is merely an example of a practical aspect that can be adopted by the internal combustion engine according to the present invention. The practical aspect of the internal combustion engine according to the present invention is not limited to the engine 200, and various known engines can be employed. It is.

  Motor generator MG1 is a motor generator having a power running function that converts electrical energy into kinetic energy and a regeneration function that converts kinetic energy into electrical energy, and is an example of the “first rotating electrical machine” according to the present invention. is there.

  Motor generator MG2 is a motor generator that is an example of a “second rotating electrical machine” according to the present invention and that is larger than motor generator MG1, and, like motor generator MG1, has a power running function that converts electrical energy into kinetic energy. And a regenerative function for converting kinetic energy into electrical energy.

  Motor generators MG1 and MG2 are configured as synchronous motor generators, and include, for example, a rotor having a plurality of permanent magnets on the outer peripheral surface and a stator wound with a three-phase coil that forms a rotating magnetic field. Of course, other configurations may be used.

  The power split mechanism 300 is a planetary gear mechanism that is an example of the “power transmission mechanism” according to the present invention.

  The power split mechanism 300 includes a sun gear S1 as an example of the “first rotating element” according to the present invention provided in the center, and a “third rotation” according to the present invention provided concentrically around the outer periphery of the sun gear S1. The ring gear R1, which is another example of the “element”, a plurality of pinion gears (not shown) which are arranged between the sun gear S1 and the ring gear R1 and revolve around the outer periphery of the sun gear S1, and each of the pinion gears And a carrier C1 as another example of the “second rotating element” according to the present invention, which supports the rotating shaft.

  The sun gear S1 is a reaction force input element that inputs a reaction force torque that antagonizes the engine torque Te to the power split mechanism 300, and is fixed to the MG1 output shaft 320 that is the output rotation shaft of the motor generator MG1. Therefore, the rotational speed of sun gear S1 is equivalent to MG1 rotational speed Nmg1, which is the rotational speed of motor generator MG1. The ring gear R1 is a power output element of the power split mechanism 300, and is connected to the power output shaft 330 so as to share its rotating shaft. As described above, the carrier C1 is coupled to the power input shaft 310 coupled to the crankshaft of the engine 200 so as to share the rotation axis thereof, and the rotation speed thereof is the engine rotation speed Ne of the engine 200. Is equivalent to

  The MG2 speed reduction mechanism 400 is connected to the first gear 410 connected to the power output shaft 330 of the power split mechanism 300 and the drive shaft 500 serving as the power output shaft of the hybrid drive device 10, and includes the first gear 410 and the third gear 430. It is a reduction gear provided with the 2nd gear 420 which meshes.

  In the MG2 reduction mechanism 400, the rotation speed of the second gear 420 is equivalent to the rotation speed of the drive shaft 500, that is, equivalent to the output rotation speed Nout of the hybrid drive device 10. Further, the number of teeth of the third gear 430 is larger than the number of teeth of the second gear 420, and the rotational speed of the drive shaft 500 is transmitted to the motor generator MG2 through the MG2 output shaft 800 in a decelerated state. Is done. Therefore, MG2 rotation speed Nmg2 that is the rotation speed of motor generator MG2 is decelerated with respect to output rotation speed Nout.

  The configuration of MG2 reduction mechanism 400 is only one form that can be adopted by a mechanism that decelerates motor generator MG2, and this type of reduction mechanism can have various forms. For example, this type of speed reduction mechanism includes a plurality of mutually rotatable components including a rotating element fixed to the drive shaft, a rotating element fixed to the fixed element, and a rotating element fixed to the rotor of the MG2. You may be comprised as a kind of differential gear mechanism containing a rotation element. Further, this type of reduction mechanism is not necessarily provided in the hybrid drive device.

  The speed reduction mechanism 600 is a gear mechanism that transmits torque between the left axle SFL and right axle SFR described above and the drive shaft 500.

  The brake mechanism 700 includes an actuator 710, an actuator output shaft 720, a sleeve SL, an MG1 side engagement element DG2, and a brake side engagement element DG1, and includes an MG1 side engagement element DG2 and a brake side engagement element DG1. , A rotationally synchronized dog clutch that is an example of an “engagement device” according to the present invention that maintains the motor generator MG1 in a non-rotatable locked state in an engaged state that is indirectly engaged through the sleeve SL. Mechanism.

  The MG1 side engagement element DG2 is a disk-like engagement member that is fixed to the MG1 output shaft 320 and rotates together with the MG1 output shaft 320. On the outer peripheral surface of the MG1 engaging element DG2, external teeth (not shown) as meshing tooth-like members are arranged at equal intervals.

  The brake side engagement element DG1 is a disk-like engagement member that is fixed to the rotation element having a rotation speed of zero, such as a chassis of the hybrid vehicle 1, that is, the MG1 side engagement element DG2 and is fixed to the fixed element. is there. On the outer peripheral surface of the brake side engagement element DG1, external teeth (not shown) as meshing tooth-like members are arranged at equal intervals. The MG1 side engagement required DG2 and the brake side engagement element DG1 are examples of “a pair of engagement elements” according to the present invention.

  The sleeve SL is an annular member that is connected to the actuator output shaft 720 and is configured to be capable of a predetermined stroke in a predetermined stroke direction (left and right direction in the drawing) by the action of an actuator 710 that drives the actuator output shaft 720. On the inner peripheral surface of the sleeve SL, internal teeth (not shown) as meshing tooth-like members are arranged at equal intervals. The internal teeth are configured to be able to mesh with the above-described external teeth respectively formed on the MG1 side engagement element DG2 and the brake side engagement element DG1 in a rotationally synchronized state. FIG. 2 illustrates a state in which the sleeve SL meshes only with the MG1 side engagement element DG2.

  Thus, in the state where the sleeve SL is engaged only with the MG1 side engagement element DG2, the MG1 side engagement element DG2 and the brake side engagement element DG1 are not engaged, and the MG1 side engagement element DG2 is engaged. Is rotatable regardless of the state of the brake-side engagement element DG1. That is, this state is a release state as an example of the “release state” according to the present invention. On the other hand, in the state where the sleeve SL has stroked a predetermined amount in the stroke direction (more specifically, the left direction in the drawing), the internal teeth formed on the sleeve SL and the external teeth of the MG1-side engagement element DG2 It meshes with the external teeth of the coupling element DG1. In this state, the MG1 side engagement element DG2 and the brake side engagement element DG1 are indirectly engaged, and the rotation of the motor generator MG1 is blocked by the brake side engagement element DG1, and the motor generator MG1 Locked to zero rotation. That is, this state is an engaged state as an example of the “engaged state” according to the present invention.

  The actuator 710 is a known direct acting electromagnetic actuator capable of applying a driving force for moving the sleeve SL in the stroke direction to the actuator output shaft 720. The actuator 710 includes a solenoid (electromagnet) as a driving force source, and an electromagnetic current that displaces the actuator output shaft 720 in the stroke direction is generated by supplying an excitation current as a driving current to the solenoid. It is a mechanism. The actuator 710 is electrically connected to the PCU 11 and can supply a drive current by supplying power from the PCU 11. Therefore, the operation state of the actuator 710 is also controlled by the ECU 100. The stroke direction of the actuator output shaft 720 is reversed by reversing the sign of the drive current.

  In the hybrid drive device 10, a rotation sensor such as a resolver is attached to a portion corresponding to the broken line frames A1, A2, and A3 shown in the figure, so that the rotation speed of the detection portion can be detected. These rotation sensors are in a state of being electrically connected to the ECU 100, and the detected rotation speed is sent to the ECU 100 at a constant or indefinite period. Supplementally, the rotational speed of the part corresponding to the illustrated broken line frame A1 is MG1 rotational speed Nmg1, and the rotational speed of the part corresponding to the illustrated broken line frame A2 is MG2 rotational speed Nmg2. Further, the rotational speed of the portion corresponding to the illustrated broken line frame A3 is the output rotational speed Nout.

  In the power split mechanism 300, the engine torque Te supplied from the engine 200 to the power input shaft 310 is transferred to the sun gear S1 and the ring gear R1 by the carrier C1 under the above-described configuration (the gear ratio between the gears). It is possible to divide the engine torque Te into two systems. At this time, in order to make the operation of the power split mechanism 300 easy to understand, when 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 carrier C1. In this case, the torque Tes acting on the sun gear S1 is expressed by the following equation (1), and the engine direct torque Ter appearing on the power output shaft 330 is expressed by the following equation (2).

Tes = −Te × ρ / (1 + ρ) (1)
Ter = Te × 1 / (1 + ρ) (2)
The configuration of the embodiment relating to the “power transmission mechanism” according to the present invention is not limited to that of the power split mechanism 300. For example, the power transmission mechanism according to the present invention may be a composite planetary gear mechanism in which a plurality of planetary gear mechanisms are combined.

<Operation of Embodiment>
<Details of shift mode>
The hybrid vehicle 1 according to the present embodiment can select a fixed gear ratio mode and a continuously variable transmission mode as the speed change mode.

  Here, the shift mode of the hybrid vehicle 1 will be described with reference to FIG. Here, FIG. 3 is an operation alignment chart illustrating one operation state of the hybrid drive apparatus 10. In the figure, the same reference numerals are assigned to the same parts as those in FIG.

  In FIG. 3A, the vertical axis represents the rotational speed, and the horizontal axis represents the sun gear S1 (uniquely motor generator MG1), carrier C1 (uniquely engine 200) and ring gear R1 (in order from the left). The motor generator MG2 and the drive shaft 500) are uniquely represented.

  Here, the power split mechanism 300 is a planetary gear mechanism having two rotational degrees of freedom constituted by a plurality of rotating elements having a differential relationship with each other, and the rotation of two elements of the sun gear S1, the carrier C1, and the ring gear R1. When the speed is determined, the rotational speed of the remaining one rotation 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.

  In FIG. 3 (a), it is assumed that the ring gear R1 that has a unique rotational relationship with the vehicle speed V and the output rotational speed Nout is rotating at a rotational speed corresponding to the illustrated white circle m1. In this case, if the motor generator MG1 is rotating at a rotation speed corresponding to the white circle g1 shown in the figure, the rotation speed of the engine 200 connected to the carrier C1, which is the remaining rotation element (that is, the engine rotation speed Ne) is inevitably. Therefore, the rotation speed corresponds to the illustrated white circle e1. At this time, while maintaining the rotation speed of the ring gear R1 (that is, uniquely maintaining the output rotation speed Nout and the MG2 rotation speed Nmg2), the rotation speed of the motor generator MG1 corresponds to the white circle g2 and the white circle g3 shown in the figure. If the speed is changed, the rotational speed of the engine 200 changes to the rotational speeds corresponding to the white circle e2 and the white circle e3 shown in the drawing, respectively.

  That is, in this case, by making the motor generator MG1 function as a rotational speed control mechanism, it means that the engine 200 has a desired operating point (here, one operating condition defined by a combination of the engine rotational speed Ne and the engine torque Te). ) Can be operated. 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 is basically controlled to the minimum fuel consumption operating point at which the fuel consumption rate of the engine 200 is minimized.

  In the continuously variable transmission mode, of course, the MG1 rotational speed Nmg1 needs to be variable. For this reason, when the continuously variable transmission mode is selected, the brake mechanism 700 is maintained in the released state described above.

  In power split mechanism 300, in order to supply torque Ter corresponding to engine torque Te described above to drive shaft 500, MG1 output shaft 320, which is the rotation shaft of sun gear S1, according to engine torque Te as MG1 torque Tmg1. It is necessary to supply the reaction torque having the same magnitude and the opposite sign (that is, negative torque) appearing on the above-described torque Tes from the motor generator MG1 to the MG1 output shaft 320.

  In this case, at the operating point in the positive rotation region such as the white circle g1 or the white circle g2, the MG1 is in a power regeneration state (that is, a power generation state) with a positive rotation negative torque. As described above, in the continuously variable transmission mode, part of the engine torque Te distributed to the sun gear shaft while supplying a part of the engine torque Te to the drive shaft by causing the motor generator MG1 to function as a reaction force element. Power regeneration (power generation) is performed at When the torque required for the drive shaft 500 (that is, the required torque of the hybrid vehicle 1) is insufficient by the direct torque from the engine 200, the regenerative power is used or power is appropriately supplied from the battery 12. The MG2 torque Tmg2 as the assist torque is appropriately supplied from the motor generator MG2 to the drive shaft.

  On the other hand, when the engine speed Ne is relatively low for a relatively high output rotational speed Nout, such as when traveling at high speed and light load, for example, the motor generator MG1 operates at an operating point in a negative rotational area such as the white circle g3 shown in the figure. It may become. 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 output from motor generator MG1 is transmitted to the drive shaft as drive torque of hybrid vehicle 1.

  On the other hand, in the hybrid drive device 10, the engines 200, MG1 and MG2 are controlled in a coordinated manner so that the sum of the engine direct torque Ter and the MG2 torque Tmg2 matches the driver request torque. When MG1 falls into a power running state, motor generator MG2 enters a negative torque state in order to absorb excessive torque supplied to drive shaft 500 relative to the required torque. In this case, motor generator MG2 is in a power regeneration state of positive rotation negative torque. In such a state, an inefficient electric path called so-called power circulation, in which the driving force from MG1 is used for power regeneration in MG2 and MG1 is driven by this regenerative power, is generated. . In the state where the power circulation occurs, the system efficiency of the hybrid drive device 10 decreases.

  Therefore, in hybrid vehicle 1, the operating state of brake mechanism 700 is controlled in the above-described engaged state, for example, in an operation region that is determined in advance such that such power circulation can occur, and motor generator MG1 is locked. The This is shown in FIG. When the MG1 side engagement element DG2 and the brake side engagement element DG1 are engaged via the sleeve SL, the MG1 rotation speed Nmg1, which is the rotation speed of the motor generator MG1, is locked to zero rotation corresponding to the illustrated white circle g4.

  In this case, the remaining engine rotational speed Ne is uniquely determined to be a rotational speed corresponding to the illustrated white circle e4 based on the output rotational speed Nout and the MG1 rotational speed Nmg1 (Nmg1 = 0). That is, when the motor generator MG1 is locked, the engine rotational speed Ne is uniquely determined by the vehicle speed V and the unambiguous output rotational speed Nout (that is, the gear ratio is constant). The transmission mode corresponding to this state is the fixed transmission ratio mode.

  In the fixed gear ratio mode, the reaction torque of the engine torque Te that should be borne by the motor generator MG1 can be replaced by the physical engagement force of the brake mechanism 700. That is, in this case, it is not necessary to control motor generator MG1 in both the power regeneration state and the power running state, and motor generator MG1 can be stopped. Therefore, basically, there is no need to operate motor generator MG2, and motor generator MG2 is in an idling state. After all, in the fixed gear ratio mode, the drive shaft torque that appears on the drive shaft 500 is only the direct torque Ter that is divided to the drive shaft side by the power split mechanism 300 out of the engine torque Te. Only the power transmission is performed, and the transmission efficiency is improved.

<Overview of switching control processing>
The request for switching the transmission mode from the fixed gear ratio mode to the continuously variable transmission mode can occur ambiguously, but if no countermeasure is taken when such a switching request is generated by the operation of the accelerator pedal by the driver, Problems that are undesirable in practice can arise. Such a problem will be described with reference to FIG. FIG. 4 is a timing chart illustrating one operating state of the hybrid vehicle 1 when switching from the fixed gear ratio mode to the continuously variable transmission mode.

  In FIG. 4, in order from the top, accelerator opening degree Ta, required driving force Ft, engine torque Te, MG2 torque Tmg2, MG1 torque Tmg1, brake torque Tclt (between MG1 side engaging element DG2 and brake side engaging element DG1) Torque) and battery charge / discharge power Pb over time.

  In FIG. 4, the accelerator opening degree Ta starts to decrease at a certain time, and as a result, the required driving force Ft changes as shown in the figure L_Ft (see the broken line), and at the time T1, from the fixed gear ratio mode to the continuously variable transmission mode. Assume that there is a request for switching the shift mode to. In addition, illustration L_F is a time transition of the driving force F of the hybrid vehicle 1.

  On the other hand, looking at the characteristics of the engine torque Te, a component (here, the drive shaft request) that should be covered by the engine torque Te out of the drive shaft request torque (an example of “request torque” according to the present invention) corresponding to the required drive force Ft. The trajectory of the engine required torque Te1 (assuming to be equal to the torque) is as shown in the figure L_Te1 (see broken line). On the other hand, the time transition of the actual engine torque Te is as shown in the figure L_Te (see solid line).

  On the other hand, when the switching request is generated, the ECU 100 causes the pair of engagement elements of the brake mechanism 700 to be in a torque non-operation state (that is, the MG1 side engagement element DG2 and the brake side engagement element in the engagement state via the sleeve SL). The MG1 torque Tmg1 is controlled so that the torque is not applied to the DG1. As a result, the MG1 torque Tmg1 represented as L_Tmg1 (see the solid line) in the figure coincides with the L_Te1reg (see the broken line in the figure), which is the locus of the reaction torque Te1reg of the engine required torque Te1, at the time T2, and substantially the reaction force. The element brake mechanism 700 is switched to the motor generator MG1 (however, the pair of engaging elements of the brake mechanism 700 are not yet released). On the other hand, in the brake mechanism 700 that no longer has to bear the reaction force torque Te1reg, the pair of engagement elements are in a torque non-actuated state, and the brake torque Tclt whose locus is represented as L_Tclt (see solid line) in the drawing is the time It becomes zero at T2.

  Here, when such switching control is executed, the torque control of the MG1 torque Tmg1 becomes difficult in the transient time region shown as a broken line frame in the time characteristic diagram of the MG1 torque Tmg1. That is, in the transitional time region as shown in the broken frame in the figure, the reaction force element that bears the reaction force torque Te1reg is switched to the motor generator MG1, but the MG1 side engagement element DG2 and the brake side engagement element DG1 are the sleeves. The state is to be called a pseudo-engagement state via SL (including the stroke execution process described above). Therefore, in order to complete the above-described stroke control of the sleeve SL that is started at time T2, the MG1 torque Tmg1 and the reaction force torque Te1reg need to change while matching each other.

  However, the engine 200 is structurally accompanied by a chemical reaction such as fuel combustion in the torque output. Therefore, the controllability is inferior to that of the electric drive type motor generator MG1, and the MG1 torque Tmg1 is slightly increased or decreased with respect to the reaction force torque Te1reg at a frequent frequency.

  Here, in particular, the shock non-operating state between the pair of engagement elements collapses, so that the rattling shock (the backlash between the MG1 side engagement element DG2 and the sleeve SL) between the pair of engagement elements via the sleeve SL. Is a value of the MG1 torque Tmg1 smaller than the reaction force torque Te1reg of the engine required torque Te1 (the reaction force). It can occur both in the case of the side that is far from zero and in the case that it is large (the side that approaches zero because of the reaction force). For this reason, in such control, not only is comfort lowered, but the brake mechanism 700 cannot be shifted to the released state.

  On the other hand, such a problem can be solved by taking the measures illustrated in FIG. Here, such a solution will be described with reference to FIG. FIG. 5 is a timing chart for explaining another operation state of the hybrid vehicle 1 at the time of switching from the fixed gear ratio mode to the continuously variable transmission mode. In the figure, the same reference numerals are given to the same portions as those in FIG. 4, and the description thereof will be omitted as appropriate. In the figure, the same reference numerals are given to the same portions as those in FIG. 4, and the description thereof will be omitted as appropriate.

  In FIG. 5, when a shift mode switching request is generated at time T1, the engine torque Te is fixed to the torque value at that time (see L_Te in the drawing). If the engine torque Te is fixed in this way, the control for matching the reaction force torque Te1reg and the MG1 torque Tmg1 becomes easier than in the case where the engine torque Te changes as shown in FIG. As a result, it is possible to realize a smooth and quick switching of the shift mode without a decrease in comfort due to a rattling shock or the like.

  By the way, with respect to L_Te1 ′ (see the chain line) corresponding to the actual engine response to the engine required torque Te1 (see L_Te1 in the figure), in a state where the engine torque remains high as shown in L_Te by fixing the torque, the engine torque Te is A large surplus with respect to the engine required torque Te1. As a result, a surplus output corresponding to the hatched portion shown in the figure is generated.

  In the control of FIG. 5, this surplus output is consumed for power regeneration in motor generator MG2. That is, the MG2 torque Tmg2 greatly decreases (that is, increases toward the regeneration side) at the time T1, and the MG2 enters a power regeneration state (see the hatched area in the drawing). As a result, the battery charge / discharge power Pb also changes to the charge side (see the hatched area in the figure).

  As described above, in the control of FIG. 5, by fixing the engine torque Te, the controllability required for the motor generator MG1 can be reduced, and the shift mode can be switched smoothly and quickly. At this time, since the motor generator MG2 consumes the surplus output for power regeneration, there is basically no problem in the power balance in the hybrid vehicle 1.

  However, in this control mode, the motor generator MG2 is generally required to have a large physique because it is necessary to realize power regeneration by the MG2 for any large driving force change. As a result, deterioration of vehicle mountability and increase in cost are unavoidable problems. The switching control process in the present embodiment leads to solving such a problem.

<Details of switching control processing>
Here, the details of the switching control process will be described with reference to FIG. FIG. 6 is a flowchart of the switching control process.

  In FIG. 6, the ECU 100 determines whether or not the release request flag FGrel is set to “1” indicating a request for switching the shift mode from the fixed gear ratio mode to the continuously variable transmission mode (step S101). Note that the release request flag FGrel is a flag set by the ECU 100 itself, and the ECU 100 can quickly execute the determination. When the release request flag FGrel is “0” that does not correspond to a request for switching the shift mode from the fixed gear ratio mode to the continuously variable transmission mode (step S101: NO), the process enters a standby state in step S101. Note that, under what conditions the switching request from the fixed gear ratio mode to the continuously variable transmission mode actually occurs, the correlation with the present invention is thin, and it is an ambiguous matter to which various known conditions can be applied. It will not be described here.

On the other hand, when the release request flag FGrel is “1” (step S101: YES), the ECU 100 acquires the required driving force Ft (step S102). The required driving force Ft is acquired from the required driving force map stored in advance in the ROM based on the vehicle speed V and the accelerator opening degree Ta.
When the required driving force Ft is acquired, the ECU 100 determines whether or not the required driving force Ft (which may be the actual driving force F) of the hybrid vehicle 1 tends to decrease (step S103). When the required driving force Ft tends to decrease (step S103: YES), that is, when the engine torque Te is fixed at a certain value, power regeneration by the motor generator MG2 (that is, charging of the battery 12) is mainly required. In this case, the ECU 100 acquires the target charge amount Pbitg (step S104).

  The target charge amount Pbitg is a target value of the charge power of the battery 12, and basically, the SOC (charge state index value) of the battery 12 is within a predetermined range (for example, a range of about 30% to 70% as the SOC value). For example, the current SOC is small if it is close to the upper limit value of the predetermined range, and it is large if it is far away. In the present embodiment, the target charge amount Pbitg is the difference between the MG2 torque Tmg2 and its minimum value (because it is on the charge side, away from zero), the power value obtained from the MG2 rotation speed Nmg2, and the charge power allowable value (charge limit) of the battery 12 Is determined according to an overall decision process based on the value Win).

  When the target charge amount Pbitg is determined, a fixed torque threshold Tefix is determined (step S105). The fixed torque threshold Tefix is a target value for fixing the engine torque Te, and is determined by the engine required torque Te1 described above, the required driving force change amount ΔFt (time change rate of Ft), and the target charge amount Pbitg. The charging side boundary value Tbdi is determined.

  The charging side boundary value Tbdi is acquired with reference to a charging side boundary value map stored in advance in the ROM. Here, the charge-side boundary value map will be described with reference to FIG. FIG. 7 is a conceptual diagram of the charging side boundary value map.

  In FIG. 7, the charge side boundary value map is a two-dimensional map having the required driving force change amount ΔFt and the target charge amount Pbitg as axis elements. As shown by the broken line in the figure, the charging side boundary value Tbdi is defined in the charging side boundary value map so that the charging side boundary value Tbdi becomes smaller as the required driving force change amount ΔFt becomes larger and becomes smaller as the target charging amount Pbitg becomes smaller. Yes. This is because, as the required driving force change amount ΔFt is larger, the regenerative power generated during power regeneration is larger, and as the target charge amount Pbitg is smaller, the power regeneration is unnecessary as the state of the battery 12. is there.

  The relationship illustrated in FIG. 7 is digitized and stored in the charge side boundary value map, and the ECU 100 selects one value corresponding to the required driving force change amount ΔFt and the target charge amount Pbitg at that time. It is the composition which acquires automatically. In the charge side boundary value map, the charge side boundary value Tbdi is set stepwise for each predetermined segment of the axis element.

  Returning to FIG. 6, in step S105, the ECU 100 determines a fixed torque threshold Tefix according to the following equation (3).

Tefix = Te1 + Tbdi (3)
When the fixed torque threshold Tefix is determined, the ECU 100 determines whether or not the engine torque Te is less than the fixed torque threshold Tefix (step S106). The range of the engine torque Te less than the fixed torque threshold Tefix is an example of the “range of output torque of the internal combustion engine” according to the present invention. When engine torque Te is equal to or greater than fixed torque threshold Tefix (step S106: NO), ECU 100 uses MG1 torque Tmg1 as a reaction force torque to be output from motor generator MG1 as Te1reg, which is a reaction force torque of engine required torque Te1. Is maintained at a sufficiently smaller value (step S108). When step S108 is executed, the process returns to step S102, and a series of processes is repeated.

  On the other hand, when the engine torque Te is less than the fixed torque threshold Tefix (step S106: YES), the ECU 100 fixes the engine torque Te to the fixed torque threshold Tefix (step S107). This is an example, and the engine torque Te does not necessarily have to be fixed to the fixed torque threshold Tefix. For example, the engine torque Te is safer than the fixed torque threshold Tefix (in this case, the power regeneration amount of the MG2 is smaller), for example, approximately in the vicinity of the fixed torque threshold Tefix obtained by multiplying the fixed torque threshold Tefix by a predetermined correction coefficient. It may be fixed to the value of.

  Here, when a little returns, in step S103, when the required driving force Ft tends to increase (step S103: NO), that is, when the engine torque Te is fixed at a certain value, torque assist by the motor generator MG2 (that is, When the discharge from the battery 12 is mainly required, the ECU 100 acquires the target discharge amount Pbotg (step S109).

  The target discharge amount Pbotg is a target value of the discharge power of the battery 12, and basically, the SOC (charge state index value) of the battery 12 is within a predetermined range (for example, a range of about 30% to 70% as the SOC value). For example, the current SOC is larger when it is close to the upper limit value of the predetermined range, and is smaller when it is far away. In the present embodiment, the target charge amount Pbotg is the difference between the MG2 torque Tmg2 and its maximum value (because it is on the discharge side, away from zero), the power value obtained from the MG2 rotation speed Nmg2, and the discharge power allowable value (discharge limit) of the battery 12 Is determined according to an overall decision process based on the value Wout).

  When the target discharge amount Pbotg is determined, a fixed torque threshold Tefix is determined (step S110). The fixed torque threshold Tefix is a target value for fixing the engine torque Te, as in step S105. The engine required torque Te1, the required driving force change amount ΔFt (time change rate of Ft), and the target are described above. It is determined based on the discharge side boundary value Tbdo determined by the discharge amount Pbotg.

  The discharge side boundary value Tbdo is acquired with reference to a discharge side boundary value map stored in advance in the ROM. Here, the discharge-side boundary value map will be described with reference to FIG. FIG. 8 is a conceptual diagram of the discharge side boundary value map.

  In FIG. 8, the discharge side boundary value map is a two-dimensional map having the required driving force change amount ΔFt and the target discharge amount Pbotg as axis elements. As indicated by the broken line in the figure, the discharge side boundary value Tbdo is defined in the discharge side boundary value map so that the discharge side boundary value Tbdo is smaller as the required driving force change amount ΔFt is larger and smaller as the target discharge amount Pbotg is smaller. Yes. This is because the larger the required driving force change amount ΔFt is, the larger the discharge power required for torque assist is. In addition, the smaller the target discharge amount Pbotg is, the more the state of the battery 12 avoids power supply to MG2. It is because it wants.

  The relationship illustrated in FIG. 8 is digitized and stored in the discharge-side boundary value map, and the ECU 100 selects one value corresponding to the required driving force change amount ΔFt and the target discharge amount Pbotg at that time. It is the composition which acquires automatically. In the discharge-side boundary value map, the discharge-side boundary value Tbdo is set stepwise for each predetermined segment of the axis element.

  Returning to FIG. 6, the ECU 100 determines the fixed torque threshold Tefix in step S110 according to the following equation (4).

Tefix = Te1-Tbdo (4)
When the fixed torque threshold Tefix is determined, the ECU 100 determines whether or not the engine torque Te is greater than the fixed torque threshold Tefix (step S111). The range of the engine torque Te larger than the fixed torque threshold Tefix is another example of the “range of output torque of the internal combustion engine” according to the present invention. When the engine torque Te is less than the fixed torque threshold Tefix (step S111: NO), the process proceeds to step S108. When engine torque Te is larger than fixed torque threshold value Tefix (step S111: YES), the process proceeds to step S107.

  In the process on the discharge side, the engine torque Te does not necessarily need to be fixed to the fixed torque threshold Tefix, as in the charge side described above. For example, the engine torque Te is safer than the fixed torque threshold Tefix (in this case, the side where the torque assist amount of MG2 becomes smaller), for example, in the vicinity of the fixed torque threshold Tefix, which is obtained by multiplying the fixed torque threshold Tefix by a predetermined correction coefficient. It may be fixed to the value of.

  When the engine torque Te is fixed at the fixed torque threshold Tefix in step S107, the ECU 100 controls the MG1 torque Tmg1 to the reaction torque Toreg of the fixed engine torque Te, assuming that the preparation for releasing the brake mechanism 700 is completed. (Step S112). When the MG1 torque Tmg1 is controlled to the reaction force torque Tereg, the actuator 710 of the brake mechanism 700 is controlled, and the sleeve SL is stroke-controlled in the release direction.

  The ECU 100 determines whether or not the shift mode switching has been completed (step S113). If the switching has not been completed (step S113: NO), the ECU 100 waits until the switching is completed. When the switching of the shift mode is completed (step S113: NO), the ECU 100 sets the release request flag FGrel to “0” (step S114) and returns the process to step S101. The switching control process is executed as described above.

  Here, the effect of the switching control processing according to the present embodiment will be described with reference to FIGS. 9 and 10. FIG. 9 is a timing chart illustrating one operation characteristic of the hybrid vehicle 1 when the target charge amount Pbitg is large when the required driving force is reduced. Similarly, FIG. 10 is a timing chart illustrating one operation characteristic of the hybrid vehicle 1 when the target charge amount Pbitg is small when the required driving force is reduced. In these drawings, the same reference numerals are given to the same portions as those in the previous drawings, and the description thereof will be omitted as appropriate.

  In FIG. 9, time transitions of the engine torque Te, the charging side boundary value Tbdi, the MG2 torque Tmg2, the MG1 torque Tmg1, the brake torque Tclt, and the battery charge / discharge amount Pb are illustrated in order from the top.

  The charge side boundary value Tbdi is affected by the required driving force change amount Δft and the target charge amount Pbitg as described above. In the initial stage of the change of the required driving force Ft, the charging side boundary value Tbdi decreases while being strongly influenced by the required driving force change amount ΔFt. However, when the decrease in the required driving force Ft stops, the effect of the target charge amount Pbitg The charging side boundary value Tbdi increases.

  On the other hand, when looking at the engine torque Te, the fixed torque threshold Tefix (see the broken line in the figure) decreases for a while after the time T10 when the shift mode switching request is generated, but when the charge side boundary value Tbdi increases, the fixed torque threshold value Tbdi increases. The torque threshold Tefix also increases. As a result, at time T11, the engine torque Te reaches the fixed torque threshold Tefix, and the engine torque Te is fixed to the fixed torque threshold Tefix.

  Here, the virtual trajectory of the engine required torque Te1 after time T11 is as shown in the chain line in the figure. When the engine torque Te is fixed at the fixed torque threshold Tefix, excessive torque corresponding to the hatched part in the figure is generated. In the present embodiment, motor generator MG2 performs power regeneration using this excess torque (see the hatched portion of Tmg2), and battery charge / discharge amount Pb changes to the charge side within a range that does not conflict with charge allowable value Pbilim. (See the hatched portion of Pb).

  The shift mode switching accompanied by the release control of the engagement element pair of the brake mechanism 700 is started at time T11, proceeds smoothly because the engine torque Te is fixed at the fixed torque threshold Tefix, and is completed at time T12. . At this time, during the period before time T11, the MG1 torque is controlled on the zero torque side with respect to the reaction force of the engine required torque Te1, and the MG1 torque Tmg1 as the reaction force torque is generated in the brake mechanism 700 by rattling and rattling. A situation that causes a shock is prevented.

  On the other hand, in FIG. 10, since the target charge amount Pbitg is small, the increase amount of the charge side boundary value Tbdi is reduced, and the fixed torque threshold Tefix is inevitably smaller than in the case of FIG. As a result, the timing at which the engine torque Te coincides with the fixed torque threshold Tefix is later than the case of FIG. 9 and becomes time T13. Since the fixed torque threshold Tefix is set on the low torque side, the regenerative electric energy of the motor generator MG2 also decreases compared to FIG. 9 as shown in the hatched portion in the figure. As a result, the charge / discharge amount Pb of the battery 12 is also more limited than in the case of FIG. This coincides with the fact that the target charge amount Pbitg is originally small. However, in this case, the allowable charging value Pbilim itself is also increasing, and the point that power regeneration is performed as much as possible within a range that does not conflict with the allowable charging value Pbilim is the same as in FIG.

  As described above, according to the present embodiment, the fixed torque threshold Tefix for fixing the engine torque Te is set not as a mere fixed value but as a variable value associated with the states of the battery 12 and the motor generator MG2. . For this reason, the fixed gear ratio mode can be canceled smoothly and quickly while maintaining the SOC of the battery 12 as much as possible in a range where there is no excess or deficiency.

Second Embodiment
Next, the switching control process according to the second embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart of the switching control process according to the second embodiment. In the figure, the same reference numerals are given to the same parts as those in FIG. 6, and the description thereof will be omitted as appropriate.

  In FIG. 11, when the charging-side fixed torque threshold value Tefix is determined in step S105, a motor assistable torque Tmg2ast is further calculated (step S201). Here, the motor assistable torque Tmg2ast is set so that driving shaft torque compensation by the motor generator MG2 can be operated not only on the charging side but also on the discharging side as in the first embodiment.

  That is, in the first embodiment described above, when the engine torque Te coincides with the fixed torque threshold Tefix, the engine torque Te is fixed to the fixed torque threshold Tefix, so that when the required driving force decreases, the required driving force increases on the charging side. In some cases, on the discharge side, the drive shaft torque is compensated by MG2. On the other hand, in the second embodiment, the motor generator MG2 and the battery 12 are used to the maximum, when the required driving force is reduced, torque assist is performed for a period of time before reaching the fixed torque threshold Tefix, and when the required driving force is increased, the fixed torque A configuration is adopted in which power regeneration is performed over a period of time before reaching the threshold Tefix. The motor assistable torque Tmg2ast is determined by the difference between the current MG2 torque Tmg2 and its maximum value (in the direction away from zero because it is on the discharge side) and the allowable discharge power value (the discharge limit value Wout may be substituted). It is determined.

  When motor assistable torque Tmg2ast is calculated, it is determined whether engine torque Te is less than a torque value corresponding to the sum of fixed torque threshold value Tefix and motor assistable torque Tmg2ast (step S202). If the engine torque Te is less than the torque corresponding to this sum (step S202: YES), the process proceeds to step S107, and if it is equal to or greater than the torque corresponding to this sum (step S202: NO), the process is step The process proceeds to step S108.

  Similarly, also in the process on the discharge side in which step S103 is branched and executed on the “NO” side, the motor assistable torque Tmg2ast is calculated after the fixed torque threshold value Tefix is calculated in step S110 (step S203). . Subsequently, it is determined whether or not the engine torque Te is larger than a torque value corresponding to the sum of the fixed torque threshold value Tefix and the motor assistable torque Tmg2ast (step S204). If engine torque Te is larger than the torque corresponding to this sum (step S204: YES), the process proceeds to step S107. If the engine torque Te is equal to or less than the torque corresponding to this sum (step S204: NO), the process proceeds to step S107. The process proceeds to step S108.

  The effect of the switching control process according to the second embodiment will be described with reference to FIG. FIG. 12 is a timing chart illustrating the operating characteristics of the hybrid vehicle 1 when the required driving force is reduced. In the figure, the same reference numerals are given to the same portions as those in FIG. 9, and the description thereof will be omitted as appropriate.

  According to FIG. 12, at the time T20 when the engine torque Te reaches the torque value obtained by adding the motor assistable torque Tmg2ast by the motor generator MG2 to the fixed torque threshold Tefix, the engine torque Te is fixed to the torque fixed threshold Tefix. . Accordingly, the torque of the drive shaft is insufficient in a temporary time region until the virtual engine torque Te1 '(refer to the chain line) intersects with the fixed torque threshold Tefix.

  This insufficient torque is compensated by providing assist torque from motor generator MG2 (see the hatched area in the figure). As a result, the battery charge / discharge amount Pb changes as efficiently as possible between the discharge allowable value Pbolim and the charge allowable value Pbilim (see the hatched portion). As described above, according to the switching control process according to the second embodiment, the motor generator MG2 is always used on both the charging side and the discharging side regardless of the direction of change in the required driving force, and the engine is as early as possible. The torque Te can be fixed, and the fixed gear ratio mode can be switched to the continuously variable transmission mode as soon as possible. Therefore, it is particularly effective in a situation where responsiveness of power performance is remarkably required.

<Third Embodiment>
Next, the switching control process according to the third embodiment of the present invention will be described with reference to FIG. FIG. 13 is a flowchart of the switching control process according to the third embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 11, and the description thereof will be omitted as appropriate.

  In FIG. 13, the ECU 100 determines whether the engine torque Te is equal to or greater than the sum of the fixed torque threshold Tefix and the motor assistable torque Tmg2ast when the required driving force Ft is decreased (step S202: NO), or the required driving. If the engine torque Te is less than the sum of the fixed torque threshold Tefix and the motor assistable torque Tmg2ast when the force Ft is increasing (step S204: NO), it is determined whether the engine torque Te is greater than zero torque. (Step S301). If engine torque Te is larger than zero torque (step S301: YES), the process proceeds to step S108.

  On the other hand, when engine torque Te is less than zero torque, that is, when the sign is reversed across zero torque (step S301: NO), ECU 100 generates a positive torque larger than reaction torque Tereg of engine torque Te from motor generator MG1. Output (step S302). By doing so, the reverse of the backlash direction in the brake mechanism 700 due to the reverse of the sign of the engine torque Te is prevented, and it is possible to prevent the occurrence of discomfort such as a backlash shock.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 14 is a timing chart illustrating the operating characteristics of the hybrid vehicle 1 in the process of executing the switching control process according to the fourth embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 12, and the description thereof is omitted as appropriate.

  First, the details of the switching control process according to the fourth embodiment will be described.

  The switching control process according to the fourth embodiment differs from the control according to the second embodiment in that the charging / discharging of the battery 12 is limited according to the engine efficiency ηe. That is, the ECU 100 acquires the engine efficiency ηe and compares it with a threshold value. When the engine efficiency ηe of the engine 200 is lower than the threshold value as a result of the comparison, (1) the target charge amount Pbitg of the battery 12 is corrected to the decreasing side when the required driving force Ft is reduced, and (2) the required driving force Ft Is increased, the motor assistable torque Tmg2ast is corrected to the decreasing side. The engine efficiency ηe is calculated by map fitting using the engine speed Ne and the engine torque Te.

  FIG. 14 illustrates the operating characteristics of the hybrid vehicle 1 when the required driving force is reduced. That is, when the engine efficiency ηe is smaller than the threshold value, the target charge amount Pbitg is corrected to the decreasing side, so the charging side boundary value Tbdi also changes to the decreasing side, and as a result, compared with the second embodiment. At slightly later timing (time T30), the engine torque Te is fixed to the fixed torque threshold Tefix. Along with this, the scale of drive shaft torque compensation by motor generator MG2 is also generally reduced, and battery charge / discharge amount Pb is operated with a comparative margin between charge allowable value Pbilim and discharge allowable value Pbolim.

  According to the fourth embodiment, by reflecting the engine efficiency ηe in the control as described above, the situation where the input / output of electric power to the battery 12 is controlled in a state where the engine efficiency is low is suppressed, and the fuel consumption of the engine 200 is deteriorated. Can be prevented.

  The present invention is not limited to the above-described embodiments, 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. The control device is also included in the technical scope of the present invention.

  The present invention can be applied to a hybrid vehicle configured to be able to switch the transmission mode between the continuously variable transmission mode and the fixed transmission ratio mode.

  DESCRIPTION OF SYMBOLS 1 ... Hybrid vehicle, 10 ... Hybrid drive device, 100 ... ECU, 200 ... Engine, 300 ... Power split mechanism, 400 ... MG2 reduction mechanism, 500 ... Drive shaft, 600 ... Reduction mechanism, 700 ... Brake mechanism, 800 ... MG2 output axis.

Claims (4)

An internal combustion engine;
A first rotating electrical machine;
A plurality of mutually differential actions including a first rotating element connected to the first rotating electrical machine, a second rotating element connected to the internal combustion engine, and a third rotating element connected to a drive shaft connected to the axle. A power transmission mechanism having a rotating element of
A second rotating electric machine capable of inputting and outputting torque with the drive shaft;
The power transmission mechanism includes a pair of engagement elements, one of which is connected to one of the rotation elements in the power transmission mechanism and the other of which is connected to a fixed element, and the pair of engagement elements are in a released state. When a continuously variable transmission mode capable of continuously changing the rotational speed of the internal combustion engine with respect to the rotational speed of the drive shaft is realized, and the pair of engagement elements are in an engaged state. And an engagement device that realizes a fixed gear ratio mode in which the rotational speed of the internal combustion engine and the rotational speed of the drive shaft are uniquely related;
A hybrid vehicle drive control device for controlling a hybrid vehicle comprising a power storage means capable of inputting and outputting electric power between the first and second rotating electrical machines,
When a request for switching the speed change mode from the fixed speed ratio mode to the continuously variable speed change mode is generated in accordance with a change in the required driving force of the driver, the electric power between the second rotating electrical machine and the power storage means is Boundary value determining means for determining a boundary value of the output torque of the drive shaft that can be compensated by input and output;
Based on the determined boundary value, a range of the output torque of the internal combustion engine that can be compensated by input / output of the electric power when maintaining the output torque of the drive shaft at the required torque corresponding to the required drive force is determined. A range determining means to perform,
Fixing means for fixing the output torque of the internal combustion engine at a torque value within the determined range in a process in which the output torque of the internal combustion engine changes in accordance with a change in the required torque accompanying a change in the required drive force; ,
Compensation control means for compensating the difference between the required torque and the output torque of the fixed internal combustion engine by the input and output of the electric power;
And a switching control means for switching the shift mode from the fixed gear ratio mode to the continuously variable transmission mode in a state where the output torque of the internal combustion engine is fixed and the difference is compensated. Drive control device. The engagement device is configured such that the pair of engagement elements rotate in the engagement state in a rotation-synchronized state in which rotations are synchronized with each other and in a back-packed state in which backlash formed in the rotation direction is packed. The hybrid vehicle drive control device according to claim 1, wherein the drive control device is a synchronous engagement device. The boundary value determining means determines the boundary value so as to decrease as the change amount of the required driving force increases and to decrease as the target charge / discharge amount of the power storage means decreases. The drive control apparatus of the hybrid vehicle of Claim 1 or 2. The output torque of the first rotating electrical machine that applies a reaction force to the internal combustion engine within the period from when the switching request is generated until the output torque of the internal combustion engine is fixed is the internal combustion engine corresponding to the required driving force. The drive control apparatus for a hybrid vehicle according to any one of claims 1 to 3, further comprising a maintenance control unit that maintains a value corresponding to less than an output torque of the engine.

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