JP2010137723A - Controller of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent reduction of drivability caused by an insufficient driving force in switching a speed change mode from a fixed speed change mode to a continuous speed change mode. <P>SOLUTION: A hybrid drive unit 1000 having an engine 200, and MG1 and MG2 and functioning as a power unit of a hybrid vehicle 10 includes a brake mechanism 400 capable of controlling MG1 in a locked state and a non-locked state by preventing rotation of a sun gear 303. In travel mode selection control, an ECU 100 calculates a driving force change rate RFt as a change rate of a request driving force Ft, and sets a high driving force side border value FtHL as an upper limit value on the driving force side in an MG1 locked region that regulates the MG1 to be in the locked state in a travel mode selection map according to the driving force change rate RFt. The ECU 100 sets a smaller high driving force side border value FtHL as the driving force change rate RFt increases. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of a control device for a hybrid vehicle including an internal combustion engine and a motor generator as power sources.

  As a device of this type, in a vehicular transmission mechanism that can be switched between a continuously variable transmission state and a stepped transmission state, a switching shock associated with switching control of the transmission state is suppressed, and durability of the engagement device is improved. The thing is proposed (for example, refer patent document 1). According to the control device for a vehicle drive device disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), when switching to the continuously variable transmission state by releasing the switching clutch or brake, the first electric motor It is said that by generating torque in the valve, reaction force torque can be appropriately transferred, and switching shock is suppressed.

JP-A-2005-278387

  In the fixed shift state where the first electric motor is locked by the brake, the power transmission efficiency is improved by avoiding the power circulation. Therefore, even if the internal combustion engine is driven in a region where the thermal efficiency is relatively low, the system efficiency of the entire hybrid vehicle is improved. However, in the conventional technique, whether or not to lock the first electric motor is determined based on the fuel efficiency that directly represents the system efficiency. However, when this type of shift state switching is performed based only on the fuel consumption, the driving force output to the axle before and after the switching may be insufficient depending on the traveling state of the vehicle, which may deteriorate drivability. There is sex. That is, the conventional technology has a technical problem that it may be difficult to switch from the fixed speed change state to the continuously variable speed change state without deteriorating drivability.

  The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a control device for a hybrid vehicle that can prevent a decrease in drivability when switching from a continuously variable transmission state to a fixed transmission state. To do.

  In order to solve the above-described problem, a control apparatus for a hybrid vehicle according to the present invention includes an internal combustion engine, a first electric motor, a second electric motor, and a first connected to the internal combustion engine capable of differential rotation. A power distribution means comprising a plurality of rotating elements including a rotating element, a second rotating element connected to the first electric motor, an output member connected to an axle, and a third rotating element connected to the second electric motor; Lock means capable of switching the state of the second rotation element between a non-rotatable locked state and an unlocked state, and depending on the state of the second rotating element, the engine rotation of the internal combustion engine is set as a travel mode. A hybrid vehicle capable of selecting a continuously variable transmission mode in which a speed ratio, which is a ratio between a speed and an output rotational speed that is the rotational speed of the output member, is continuously variable, and a fixed speed mode in which the speed ratio is fixed System A device for specifying a degree of change in the required driving force of the hybrid vehicle, a setting unit for setting the driving mode switching condition according to the specified degree of change, and the set And control means for switching the travel mode by controlling the lock means based on a switching condition.

  The power distribution means according to the present invention may be a first motor that can take an internal combustion engine, for example, a motor generator such as a motor generator as a preferred form, and a second motor that can take a motor generator such as a motor generator, as a preferred form. A plurality of rotational elements that can be differentially rotated with each other, including first, second, and third rotational elements that are connected to or connectable to each power source of the electric motor (that is, corresponding to each power source) The rotating element is at least a part of the rotating element provided in the power distribution means, but not necessarily all). As a preferred form, for example, the first, second, and third rotating elements are respectively carriers. It takes the form of a planetary gear mechanism or the like provided with a sun gear and a ring gear.

  Further, the lock means according to the present invention is a means configured to be capable of switching at least binary between the locked state and the unlocked state of the second rotating element that can be connected to the first electric motor. Yes, as a preferable form, for example, engaging means that can take various forms such as a friction engagement type or a meshing type (including a brake device, a clutch device, etc. as a preferable form, and engaging elements are mutually engaged and separated. Various drive devices that can be driven to achieve this, and various detection means for detecting the physical state of the engagement element, etc., as appropriate). Here, the “locked state” is a state in which, for example, a physical, mechanical, electrical, or magnetic deterrent is fixed so as not to rotate, and the non-locked state is not in such a locked state. In other words, it refers to a rotatable state.

  The hybrid vehicle according to the present invention may be directly or indirectly separated from the output shaft of the internal combustion engine, such as a crankshaft, and the axle, depending on the state of the second rotating element that is appropriately and selectively switched by the locking means. It is possible to switch a running mode, which means a control mode of a rotational speed ratio (hereinafter referred to as “speed ratio” as appropriate) with the output member to be connected, between a continuously variable transmission mode and a fixed transmission mode. is there. At this time, the number of gears belonging to one travel mode may be single or plural.

  Here, the “continuously variable transmission mode” corresponds to the case where the second rotating element is in an unlocked state, and the transmission ratio is theoretically, substantially or preliminarily defined as a physical, mechanical Refers to a speed ratio control mode that can be continuously changed (including a stepped mode equivalent to being practically continuous) within the scope of mechanical, mechanical, or electrical constraints. As one embodiment, the second rotating element is a reaction force element that bears the reaction torque of the internal combustion engine, and the rotation speed is controlled by the first electric motor connected to the second rotating element in the unlocked state. It is realized by. In the continuously variable transmission mode, the operating point of the internal combustion engine (for example, a point defining one operating condition of the internal combustion engine defined by the engine rotational speed and the output torque) is, for example, theoretically, substantially or somehow For example, the fuel consumption is controlled to an optimum fuel consumption operating point that can be theoretically, practically or minimally (maximum in terms of mileage per unit fuel amount) within some constraints. The

  The “fixed speed change mode” corresponds to a case where the second rotation element is in a locked state, and refers to a control mode in which the speed ratio is fixed to a single value. In the fixed speed change mode, the engine rotational speed is inevitably defined uniquely according to the vehicle speed of the hybrid vehicle. As is clear from the fact that the fixed speed change state is obtained when the second rotation element is in the locked state, the power distribution means is preferably the first rotation element or the rotation that can rotate integrally with the first rotation element. Three types of rotating elements or rotating element groups: an element group, a rotating element group that can rotate integrally with the second rotating element or the second rotating element, and a rotating element group that can rotate integrally with the third rotating element or the third rotating element The differential mode is defined so that the rotational speed of the remaining one rotating element or rotating element group is unambiguously defined when the rotating speed of two types of rotating elements or rotating element groups is specified. Yes.

  In the control apparatus for a hybrid vehicle according to the present invention, the switching of the traveling mode between the continuously variable transmission mode and the fixed transmission mode is performed by, for example, various processing units such as an ECU (Electronic Control Unit), various controllers, or a microcomputer. The control means that can take the form of various computer systems such as devices is based on the switching conditions set by the setting means that can take the form of various processing units such as ECUs, various controllers or various computer systems such as microcomputer devices, for example. This is realized by controlling the locking means. That is, when the locking means is controlled so that the second rotating element is in the locked state, the above-described fixed shift mode is performed, and when the locking means is controlled so that the second rotating element is in the unlocked state. The continuously variable transmission mode is used for power transmission in the hybrid vehicle.

  On the other hand, in the fixed speed change mode, the hybrid vehicle basically travels only by the output torque of the internal combustion engine (since the second electric motor is connected to the output member via the third rotation element, the internal combustion engine and the first Although torque can be supplied to the output member regardless of the state of the motor, the required torque cannot always be output depending on the SOC (State Of Charge) of the power storage means, and the first motor generates power. In the fixed transmission mode in which the second motor cannot be performed, it is desirable that the second electric motor is also stopped in order to prevent the SOC from decreasing. For this reason, the region of the required driving force in which the fixed speed change mode can be selected (that is, the conditions for switching the driving mode) are determined by the gear ratio between the rotating elements of the power distribution means and the maximum driving force of the internal combustion engine. Thus, the upper limit is physically defined.

  Here, for example, when the traveling mode is switched from the fixed speed change mode to the continuously variable speed change mode, the rotational speed of the first electric motor in the stopped state is quickly increased to the target rotational speed, and the first electric motor, the second electric motor, and the internal combustion engine It is necessary to quickly change the operating point of each engine to the operating point to be taken in the continuously variable transmission mode. However, since the rotation of the first motor is stopped in the fixed speed change mode, the target rotation speed is reached by the influence of inertia acting on the first motor until the rotation speed of the first motor reaches the target rotation speed. Regardless of the magnitude of the difference in height, it is unavoidable that a corresponding time delay can occur. In a transitional period corresponding to this time delay, a part of the output torque of the internal combustion engine is consumed for the rotation increase of the first electric motor which is a reaction force element, and the substantial torque appearing on the drive shaft is reduced. For this reason, the driving force applied to the axle via the drive shaft is likely to be insufficient, and the reduction in power performance is likely to become obvious. Such a decrease in power performance is an element that causes a decrease in drivability.

  In particular, this insufficient driving force can be compensated for by increasing the output torque of the internal combustion engine. However, when this type of travel mode switching occurs in a manner that is limited by the above physical upper limit, Since the engine cannot output more torque, the above-described lack of driving force cannot be avoided. At this time, even if the second motor applies torque to the drive shaft to make up for the driving force that is insufficient due to the electric power supplied from the power storage means, the operation of the second motor is limited by the SOC of the power storage means. Therefore, there is no guarantee that this kind of driving force assistance is always obtained.

  On the other hand, this kind of driving mode switching is performed within a range less than the physical limit described above (that is, a margin is set in advance to the upper limit value of the required driving force that defines the selection region of the fixed transmission mode). In this case, since the internal combustion engine still has an operational margin up to the physical upper limit value, it is possible to increase the output torque and compensate for the lack of driving force during the transitional period. However, the driving conditions of hybrid vehicles vary greatly depending on the driving environment, the driver, and the situation from time to time, and when this kind of margin is set without any guidelines. However, a decrease in drivability due to a lack of driving force is not necessarily eliminated. Alternatively, if this kind of margin is set excessively large, the angular power circulation (that is, the first electric motor is driven in the power running region by the fixed speed change mode, and the surplus driving force appearing in the output member is regenerated by the second electric motor. (This refers to the generation of an inefficient electric path, such as driving the first motor with regenerative power), but the benefits cannot be fully enjoyed, resulting in a decrease in system efficiency. It might be.

  Therefore, in the control apparatus for a hybrid vehicle according to the present invention, the setting means is a required driving force specified by a specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. The driving mode switching condition is set so as to accompany a binary, stepwise or continuous change according to the degree of the change. The “specific” according to the present invention is a concept that encompasses detection, estimation, calculation, derivation, identification, acquisition, and the like, and the specific target (in this case, the degree of change in driving force), regardless of whether it is true or false. As long as the correction means can finally grasp the information as information that can be referred to in the control, the process may have various aspects.

  The degree of change in the required driving force depends on the operation of the internal combustion engine that is necessary to prevent a decrease in drivability due to a lack of driving force when switching between driving modes (at least not let the driver perceive that effect). It correlates with the size of the remaining power (that is, the size of the margin required for the physical upper limit). That is, for example, in a situation where the required driving force tends to change relatively greatly, such as during sudden acceleration, the shortage of the driving force is reliably compensated (the required driving force is output from the internal combustion engine before the power supply in the continuously variable transmission mode is started). In order not to exceed the driving force corresponding to the physical upper limit of the torque), it is necessary to take a relatively large amount of the margin, and when the change in the required driving force is relatively small, the amount of the margin Is relatively small. Therefore, when the switching condition is set according to the degree of change in the required driving force, it is possible to maintain the fixed speed change mode as much as possible without causing a driving force shortage and improve the system efficiency. It becomes.

  Supplementally, there is no guarantee that driving force deficiency can be reliably eliminated, and fixed transmission mode is possible in at least the category of technical ideas in which the driving mode switching conditions are unambiguous at least for changes in required driving force. It is difficult to maintain the system efficiency by maintaining the system efficiently. That is, according to the control apparatus for a hybrid vehicle according to the present invention, it is possible to obtain in the fixed transmission mode while preventing a decrease in drivability when switching the traveling mode between the fixed transmission mode and the continuously variable transmission mode. It is clearly superior to this kind of technical idea in that the practical benefits related to the improvement of system efficiency can be secured as much as possible.

  In one aspect of the hybrid vehicle control device according to the present invention, the switching condition is defined such that the fixed speed change mode is selected when the required driving force is a predetermined upper limit value or less. The setting means sets the upper limit value so as to decrease as the specified degree of change increases.

  According to this aspect, the driving mode switching condition is fixed when the required driving force is equal to or less than a predetermined upper limit value (which may be the physical upper limit or a value less than that). Since it is defined that the speed change mode is selected, it is possible to quickly and accurately determine whether or not the travel mode needs to be switched. Such an upper limit value of the required driving force may not be all of the switching conditions. In view of the fact that the engine rotational speed of the internal combustion engine is unambiguous with the vehicle speed in the fixed speed change mode, the vehicle speed or its correlation. A part of the switching condition may be defined based on the value. Similarly, conditions may be set as appropriate for the lower limit value of the required driving force.

  Here, the setting means sets the upper limit value so that the magnitude of the specified degree of change corresponds to the magnitude. For this reason, for example, when the degree of change in the required driving force is relatively large, such as during sudden acceleration, a large margin for the driving force in the transitional period related to the switching of the driving mode is taken, and the shortage of driving force is reliably resolved. Is done.

  In this aspect, the setting means sets the upper limit value so as to be larger than that in a normal state when a predetermined input in which a degree of change in the required driving force is previously small is generated. May be.

  According to this aspect, for example, the driver can be obtained by artificially operating various operation means (for example, a button, a lever, or a dial) in the vehicle, or the driving condition or driving condition of the hybrid vehicle can be obtained. Based on an appropriate controller or the like, the threshold value is reduced according to a predetermined input, which is automatically output regardless of the driver's intention (preferably making a determination that the driver has the intention). The amount of correction at the time of correction is reduced.

  Here, the predetermined input means that the degree of change in the required driving force is small compared to the normal time (which indicates a period in which this type of input does not occur), or a determination to that effect is made. In a preferred form, for example, the operation of an economy button corresponding to the priority on economy should be avoided, and the slipping or locking of the drive wheels should be prevented. This refers to the operation of a snow button or the operation of an execution button for cruise control control in which the required driving force is determined according to the deviation between the target vehicle speed and the actual vehicle speed.

  When this type of input is made, the amount of margin with respect to the physical upper limit to be set with respect to the degree of change in one driving force is greater, even if the degree of change in driving force itself changes more or less. It's small. Accordingly, the fixed speed change mode can be maintained in a wider range, and the benefits related to the improvement of the system efficiency can be enjoyed more suitably. In addition, when this type of input occurs, at least the first requirement of the driver is not in the power performance, so even if the driving force is somewhat insufficient during the transitional period, the rising of the driving force becomes slow. However, the driver is less likely to feel uncomfortable. That is, according to this aspect, ensuring of system efficiency and securing of drivability can be made compatible with each other in a form more reflecting the driver's intention, which is extremely useful in practice.

  In another aspect of the hybrid vehicle control device according to the present invention, the degree of change in the required driving force is a change rate of the required driving force.

  According to this aspect, the required driving force obtained periodically or aperiodically based on the vehicle speed, the accelerator opening degree, or the like is time-processed, so that the degree of change in the required driving force can be specified relatively easily. It becomes possible.

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

<Embodiment of the Invention>
Various preferred embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the hybrid vehicle 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the hybrid vehicle 10.

  In FIG. 1, the hybrid vehicle 10 includes an ECU 100, a PCU (Power Control Unit) 11, a battery 12, a vehicle speed sensor 13, an accelerator opening sensor 14, and a hybrid drive device 1000 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 10. It is an example of a “control device for a hybrid vehicle”. The ECU 100 is configured to be able to execute a travel mode selection control described later in accordance with a control program stored in the ROM. The ECU 100 is an integrated electronic control unit configured to function as an example of each of the “control means”, “specification means”, and “correction means” according to the present invention. All 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 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. 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 (that is, In this case, the control unit is configured to be capable of controlling power transfer between the motor generators without using 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 is a rechargeable power storage unit configured to be able to function as a power supply source related to power for powering the motor generator MG1 and the motor generator MG2.

  The vehicle speed sensor 13 is a sensor configured to be able to detect the vehicle speed V of the hybrid vehicle 10. The vehicle speed sensor 13 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.

  The accelerator opening sensor 14 is a sensor configured to be able to detect an accelerator opening Ta that is an operation amount of an accelerator pedal (not shown) of the hybrid vehicle 10. The accelerator opening sensor 14 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 hybrid drive device 1000 is a power unit that functions as a power train of the hybrid vehicle 10. Here, a detailed configuration of the hybrid drive apparatus 1000 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram conceptually showing the configuration of the hybrid drive apparatus 1000. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  In FIG. 2, the hybrid drive device 1000 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”), a brake mechanism. 400 and a speed reduction mechanism 500.

  The engine 200 is a gasoline engine which is an example of the “internal combustion engine” according to the present invention, and is configured to function as a main power source of the hybrid vehicle 10. Here, the detailed configuration of the engine 200 will be described with reference to FIG. FIG. 3 is a schematic view illustrating a cross-sectional configuration of the engine 200. In the figure, the same reference numerals are given to the same portions as those in FIGS. 1 and 2, and the description thereof is omitted as appropriate. The “internal combustion engine” in the present invention includes, for example, a 2-cycle or 4-cycle reciprocating engine, and has at least one cylinder, and various fuels such as gasoline, light oil, alcohol, etc. in the combustion chamber inside the cylinder. Includes an engine configured to be able to take out the force generated when the air-fuel mixture containing gas is burned as a driving force through appropriate physical or mechanical transmission means such as pistons, connecting rods and crankshafts. It is a concept to do. As long as the concept is satisfied, the configuration of the internal combustion engine according to the present invention is not limited to that of the engine 200 and may have various aspects.

  In FIG. 3, the engine 200 burns the air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and the explosive force due to such combustion. The reciprocating motion of the piston 203 generated in response to the above is converted into the rotational motion of the crankshaft 205 as the engine output shaft via the connecting rod 204.

  In the vicinity of the crankshaft 205, a crank position sensor 206 for detecting the rotational position (ie, crank angle) of the crankshaft 205 is installed. The crank position sensor 206 is electrically connected to the ECU 100 (not shown), and the ECU 100 calculates the engine speed NE of the engine 200 based on the crank angle signal output from the crank position sensor 206. It is the composition which becomes.

  The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a direction perpendicular to the paper surface. However, since the configurations of the individual cylinders 201 are equal to each other, in FIG. Only the cylinder 201 will be described. Further, the number of cylinders and the arrangement form of each cylinder in the internal combustion engine according to the present invention are not limited to those of the engine 200 as long as the above-described concept is satisfied, and may take various forms, for example, 6 cylinders, 8 cylinders or 12 cylinders. It may be a cylinder engine, V-type, horizontally opposed type, or the like.

  In the engine 200, air sucked from the outside passes through the intake pipe 207 and is guided into the cylinder 201 through the intake port 210 when the intake valve 211 is opened. On the other hand, the fuel injection valve of the injector 212 is exposed at the intake port 210, so that fuel can be injected into the intake port 210. The fuel injected from the injector 212 is mixed with the intake air before and after the opening timing of the intake valve 211 to become the above-described mixture.

  The fuel is stored in a fuel tank (not shown), and is supplied to the injector 212 via a delivery pipe (not shown) by the action of a feed pump (not shown). The air-fuel mixture combusted inside the cylinder 201 becomes exhaust, and is led to the exhaust pipe 215 via the exhaust port 214 when the exhaust valve 213 that opens and closes in conjunction with the opening and closing of the intake valve 211 is opened.

  On the other hand, on the upstream side of the intake port 210 in the intake pipe 207, a throttle valve 208 for adjusting the amount of intake air related to the intake air guided through a cleaner (not shown) is disposed. The throttle valve 208 is configured such that its drive state is controlled by a throttle valve motor 209 electrically connected to the ECU 100. The ECU 100 basically controls the throttle valve motor 209 so as to obtain a throttle opening corresponding to the opening of an accelerator pedal (not shown) (that is, the accelerator opening Ta described above). It is also possible to adjust the throttle opening without intervention of the driver's intention through the operation control of 209. That is, the throttle valve 208 is configured as a kind of electronically controlled throttle valve.

  A three-way catalyst 216 is installed in the exhaust pipe 215. The three-way catalyst 216 is configured to be able to purify CO (carbon monoxide), HC (hydrocarbon), and NOx (nitrogen oxide) discharged from the engine 200, respectively. The form of the catalytic device according to the present invention is not limited to such a three-way catalyst. For example, instead of or in addition to the three-way catalyst, various catalysts such as an NSR catalyst (NOx storage reduction catalyst) or an oxidation catalyst are used. May be installed.

  An air-fuel ratio sensor 217 configured to be able to detect the exhaust air-fuel ratio of the engine 200 is installed in the exhaust pipe 215. Further, a water temperature sensor 218 for detecting the cooling water temperature related to the cooling water (LLC) circulated and supplied to cool the engine 200 is disposed in the water jacket installed in the cylinder block that houses the cylinder 201. ing. The air-fuel ratio sensor 217 and the water temperature sensor 218 are electrically connected to the ECU 100, and the detected air-fuel ratio and cooling water temperature are grasped by the ECU 100 at a constant or indefinite detection cycle. .

  Returning to FIG. 2, motor generator MG <b> 1 is a motor generator that is an example of a “first motor” according to the present invention, and includes a power running function that converts electrical energy into kinetic energy, and a regeneration function that converts kinetic energy into electrical energy. It is the composition provided with. The motor generator MG2 is a motor generator that is an example of a “second motor” according to the present invention. Like the motor generator MG1, the motor generator MG2 converts a power running function that converts electrical energy into kinetic energy, and converts kinetic energy into electrical energy. It has a configuration with a regenerative function. Motor generators MG1 and MG2 are configured as, for example, synchronous motor generators, and include, for example, a rotor having a plurality of permanent magnets on an outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field. It may have, and may have other composition.

  The power split mechanism 300 includes a sun gear 303 that is an example of a “second rotating element” according to the present invention provided in the center, and a “third rotation” according to the present invention that is provided concentrically on the outer periphery of the sun gear 303. The ring gear 301, which is an example of the “element”, the plurality of pinion gears 305 that are arranged between the sun gear 303 and the ring gear 301 and revolve while rotating on the outer periphery of the sun gear 303, and the rotation shafts of these pinion gears are pivotally supported. This is a power transmission device as an example of “power distribution means” according to the present invention, including a planetary carrier 306 as an example of “first rotating element” according to the present invention.

  Here, the sun gear 303 is coupled to the rotor (not shown) of the MG1 via the sun gear shaft 304, and the rotation speed thereof is equivalent to the rotation speed of the MG1 (hereinafter referred to as “MG1 rotation speed Nmg1” as appropriate). It is. The ring gear 301 is coupled to a rotor (not shown) of the MG 2 via a drive shaft 302 (that is, an example of an “output member” according to the present invention) and a speed reduction mechanism 500, and the rotational speed thereof is the rotation of the MG 2. This is equivalent to the speed (hereinafter referred to as “MG2 rotational speed Nmg2” as appropriate). Further, the planetary carrier 306 is coupled to the crankshaft 205 of the engine 200, and the rotation speed thereof is equivalent to the engine rotation speed NE of the engine 200.

  On the other hand, the drive shaft 302 is a drive shaft SFR and SFL that respectively drive the right front wheel FR and the left front wheel FL that are drive wheels of the hybrid vehicle (that is, these drive shafts are examples of the “axle” according to the present invention). These are connected via a reduction mechanism 500 as a reduction device including various reduction gears such as a differential. Therefore, the motor torque output from the motor generator MG2 to the drive shaft 302 is transmitted to each drive shaft via the speed reduction mechanism 500, and similarly, the drive force from each drive wheel transmitted via each drive shaft is Then, it is input to the motor generator MG2 via the speed reduction mechanism 500 and the drive shaft 302. That is, the rotational speed of the motor generator MG2 is uniquely related to the vehicle speed V of the hybrid vehicle 10.

  Under such a configuration, the power split mechanism 300 transmits power generated by the engine 200 to the sun gear 303 and the ring gear 301 by the planetary carrier 306 and the pinion gear 305 (a ratio corresponding to the gear ratio between the gears). And the power of the engine 200 can be divided into two systems.

  The configuration of the embodiment relating to the “power distribution means” according to the present invention is not limited to that of the power split mechanism 300. For example, the power distribution means according to the present invention includes a plurality of planetary gear mechanisms, and a plurality of rotating elements provided in one planetary gear mechanism are appropriately connected to each of a plurality of rotating elements provided in another planetary gear mechanism, An integral differential mechanism may be configured. In addition, the speed reduction mechanism 500 according to the present embodiment merely reduces the rotational speed of the drive shaft 302 in accordance with a preset reduction ratio, but the hybrid vehicle 10 includes, for example, a plurality of speed reduction devices separately from this type of speed reduction device. A stepped transmission device including a plurality of shift speeds including the clutch mechanism and the brake mechanism as a component may be provided.

  The brake mechanism 400 is a brake device as an example of the “locking unit” according to the present invention having a configuration in which one brake plate is connected to the sun gear 303 and the other brake plate is physically fixed. The brake mechanism 400 is connected to a hydraulic drive device (not shown), and the sun gear brake plate is pressed against the fixed brake plate by the supply of hydraulic pressure from the hydraulic drive device, so that the state of the sun gear 303 cannot be rotated. It is configured to be selectively switchable between a locked state and a rotatable non-locked state. Note that the hydraulic drive device of the brake mechanism 400 is electrically connected to the ECU 100, and the ECU 100 is configured to control the operation thereof at a higher level.

<Operation of Embodiment>
In the hybrid vehicle 10 according to the present embodiment, it is possible to select two types of travel modes, the continuously variable transmission mode and the fixed transmission mode, according to the state of the sun gear 303 described above (uniquely, the state of the motor generator MG1). It is. Here, the travel mode of the hybrid vehicle 10 will be described with reference to FIG. FIG. 4 is an operation alignment chart for explaining the operation state of each part of the hybrid drive apparatus 1000. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof will be omitted as appropriate.

  In FIG. 4A, the vertical axis represents the rotation speed, and the horizontal axis represents the motor generator MG1, the engine 200, and the motor generator MG2 in order from the left. Here, power split device 300 is constituted by a planetary gear mechanism, and includes sun gear 303 (ie, substantially MG1), planetary carrier 306 (ie, substantially engine 200) and ring gear 301 (ie, substantially). If the rotational speed of two elements of MG2) is determined, the rotational speed of the remaining one element is inevitably determined. That is, the operation state of each element on the alignment chart can be represented by one straight line (operation collinear line) for one operation state of the hybrid drive apparatus 1000.

  For example, in FIG. 4A, if the operating point of the motor generator MG2 is the white circle m1 shown in the figure and the operating point of the motor generator MG1 bearing the reaction torque of the engine 200 is the white circle m3 shown in FIG. The point inevitably becomes the illustrated white circle m2. Here, if the vehicle speed V (that is, unambiguous with the MG2 rotational speed Nmg2) is constant, the MG1 rotational speed Nmg1 is controlled to change the operating point of MG1 to the white circle m4 or the white circle m5 shown in the figure. The operating point of the engine 200 changes to a white circle m6 or a white circle m7 shown in the drawing. Thus, the travel mode in which motor generator MG1 is used as the rotational speed control device and engine 200 can be operated at a desired operating point is the continuously variable transmission mode. In the continuously variable transmission mode, the operating point of the engine 200 is basically controlled to the optimum fuel consumption operating point at which the fuel consumption rate of the engine 200 is minimized for each required output.

  Here, when driving at high speed and light load, etc., under operating conditions where the MG2 rotational speed Nmg2 is high but the engine rotational speed NE is low, the operating point of the motor generator MG1 is set to the negative rotational side, for example, the white circle m5 shown in the figure. May need to be done. In this case, motor generator MG1 outputs a negative torque as a reaction torque of engine 200, enters a state of negative rotation negative torque, and enters a power running state. That is, in this case, the output torque of motor generator MG 1 is transmitted to drive shaft 302 as the drive torque of hybrid vehicle 10. On the other hand, motor generator MG2 is in a negative torque state because it absorbs excessive torque with respect to the required torque output to drive shaft 302. In this case, motor generator MG2 is in a state of positive rotation and negative torque and is in a power generation state. In such a state, an electric path called so-called power circulation is generated in which MG2 generates power with the driving force from MG1 and MG1 is driven with this generated power. In the state where the power circulation occurs, the power transmission efficiency decreases, the system efficiency of the hybrid drive apparatus 1000 (for example, defined as the thermal efficiency of the engine 200 × the transmission efficiency, etc.) decreases, and eventually the fuel consumption of the engine 200 The rate will drop.

  Therefore, in an operation region where such power circulation can occur, the sun gear 303 is controlled by the brake mechanism 400 to the locked state described above. This is shown in FIG. When sun gear 303 is locked, inevitably motor generator MG1 is also locked, and MG1 rotation speed Nmg1 is zero (see white circle m8 in the figure). Therefore, the engine rotational speed NE of the engine 200 is uniquely determined by the vehicle speed V, the unambiguous MG2 rotational speed Nmg2 and the Nmg1 (that is, the gear ratio is constant), and the operating point is the white circle m9 shown in the figure. Become. Thus, the traveling mode corresponding to the case where MG1 is in the locked state is the fixed speed change mode.

  In the fixed speed change mode, the reaction force torque of the engine 200 that should be borne by the motor generator MG1 can be replaced by the physical braking force of the brake mechanism 400. That is, it is not necessary to control motor generator MG1 in the power generation state or the power running state, and motor generator MG1 is stopped. Therefore, basically, motor generator MG2 is also controlled to be in a stopped (electrically stopped) state, and is in an idling state. After all, in the fixed speed change mode, the torque output from the hybrid drive device 1000 is only a part of the engine torque TE that is divided to the drive shaft 302 side by the power split mechanism 300. Here, if the gear ratio between the ring gear 301 and the sun gear 303 is ρ, the engine torque Tout appearing on the drive shaft 302 side (which defines the drive force applied to the drive shaft) is expressed by the following equation (1). .

Tout = (1 / (1 + ρ)) · TE (1)
Thus, in the fixed speed change mode, only the engine torque becomes the driving torque of the hybrid vehicle 10 (note that the driving torque is unambiguous with the driving force applied to each drive shaft), and the hybrid driving apparatus 1000 is mechanically Only power transmission is performed, and transmission efficiency is increased.

  In the hybrid vehicle 10, the travel mode is appropriately selected by travel mode selection control executed by the ECU 100. Here, the details of the traveling mode selection control will be described with reference to FIG. FIG. 5 is a flowchart of the travel mode selection control.

  In FIG. 5, the ECU 100 acquires the required driving force Ft of the hybrid vehicle 10 (step S101). The required driving force Ft is a required value of the driving force applied to each drive shaft, and the required driving using the vehicle speed V detected by the vehicle speed sensor 14 and the accelerator opening Acc detected by the accelerator opening sensor 13 as parameters. Obtained from force map. The acquired required driving force Ft is stored in the RAM for at least two including the latest value.

  When the required driving force Ft is acquired, the ECU 100 refers to the required driving force Ft acquired in step S101 and stored in the RAM, and calculates a driving force change rate RFt that is a change rate of the required driving force Ft (step S102). The driving force change rate RFt is a value obtained by dividing the difference between the latest value and the previous value by the acquisition cycle of the required driving force Ft, and is an example of the “degree of change in the required driving force” according to the present invention. This is merely an example, and the “degree of change in required driving force” according to the present invention may be, for example, a difference between the latest value of the acquired required driving force and the previous value. The operation according to step S102 is an example of the operation according to the “specifying means” according to the present invention.

  When the driving force change rate RFt is calculated, the ECU 100 sets a traveling mode switching condition (step S103). Here, in the present embodiment, the traveling mode switching condition is defined on a traveling mode selection map using the required driving force Ft and the vehicle speed V as parameters. The operation according to step S103 is an example of the operation of the “setting unit” according to the present invention.

  Here, the details of the travel mode selection map will be described with reference to FIG. FIG. 6 is a schematic diagram of a travel mode selection map.

  In FIG. 6, the travel mode selection map is a two-dimensional map in which the required driving force Ft and the vehicle speed V are represented on the vertical axis and the horizontal axis, respectively. On the map, an area in which the MG1 is controlled to be locked and the fixed speed change mode is to be selected is defined as an MG1 lock area (shown hatched area).

  Here, the low speed side boundary value VLL that defines the low vehicle speed side boundary of the MG1 lock region is defined by the minimum rotational speed of the engine 200. That is, in the fixed speed change mode realized by the MG1 being locked, the engine 200 and the drive shaft 302 are directly connected, but the vehicle speed V is reduced regardless of whether the engine 200 can rotate independently. Therefore, the low speed side boundary value VLL is determined in advance so that the engine 200 is not misfired or stalled.

  In hybrid vehicle 10, an EV travel mode in which hybrid vehicle 10 travels using only the power of motor generator MG 2 (EV travel mode is also an example of the “travel mode” according to the present invention) is selected. Is also possible. Therefore, the low speed side boundary value VLL may be associated with the selection condition of the EV traveling mode instead of or in addition to the above-described low speed side operation limit of the engine 200. However, in EV traveling, it is only necessary to output motor torque from the motor generator MG2 to the drive shaft 302, and there is no hindrance to the performance when the engine 200 is in the engine stop state. It can be selected regardless of whether it is locked or not.

  Further, the high speed side boundary value VHL that defines the high vehicle speed side boundary of the MG1 lock region is defined by the upper limit rotational speed (so-called rev limit) of the engine 200. In other words, since the engine speed NE of the engine 200 is unambiguous with the vehicle speed V, in the hybrid vehicle 10 in the state where the fixed speed change mode is selected, the vehicle speed V exceeds the upper limit value of the engine speed NE. It is impossible to raise. Whether or not a higher vehicle speed is required is determined based on the vehicle speed V and the accelerator opening degree Acc at that time. However, if a higher vehicle speed is required, the required driving force Ft is eventually reduced as described later. The fixed driving mode is canceled in response to a request from the driving force side.

  On the other hand, the low driving force side boundary value FtLL (see the broken line in the figure) that defines the low driving force side boundary of the MG1 lock region is determined based on the system efficiency of the hybrid drive device 1000. Since the hybrid drive apparatus 1000 includes MG1 and MG2 as power sources, an engine having a combustion form that prioritizes thermal efficiency over the maximum output is often used as the engine 200 in many cases. However, basically, the thermal efficiency of the engine has a best point in a region on the high rotation side and the high load side to some extent, and the thermal efficiency is often extremely deteriorated on the low rotation side or the light load side. For this reason, in the region where the required driving force is low, even if the transmission efficiency is improved by the fixed speed change mode, the reduction in thermal efficiency exceeds that, and the continuously variable speed mode should be selected as the system efficiency of the hybrid drive device 1000. May be better. Therefore, the low driving force side boundary value FtLL increases as the vehicle speed decreases.

  On the other hand, the boundary on the high driving force side of the MG1 lock region is defined by the high driving force side boundary value FtHL (an example of the “predetermined upper limit value” according to the present invention, see the chain line in the drawing). In step S103, the high driving force side boundary value FtHL that defines the high driving force side boundary is set. For example, when considering the case where the driving force change rate RFt calculated in step S102 is RFt1 and the case where RFt2 (RFt2> RFt1), the high driving force side boundary value when RFt = RFt1 is The boundary value on the high driving force side when FtHL2 and RFt = RFt2 is FtHL1 (FtHL1 <FtHL2). That is, the higher the driving force change rate RFt, the lower the high driving force side boundary value FtHL of the MG1 lock region, and the MG1 lock region becomes narrower. In FIG. 6, the high driving force side boundary value FtHL is not changed according to the vehicle speed V, but this is only an example, and the high driving force side boundary value may be variable according to the vehicle speed V. .

  Supplementing the high driving force side boundary value FtHL, the upper limit value of the engine torque appearing on the drive shaft 302 in the fixed speed change mode is (1 / (1 + ρ)) · TEmax (where TEmax is the engine) according to the above-described equation (1). 200 maximum torque). Therefore, the upper limit value of the high driving force side boundary value FtHL is limited to the upper limit value of the engine torque appearing on the drive shaft 302. Assuming that the upper limit value of the high driving force side boundary value FtHL is FtHLmax, in step S103, the ECU 100 calculates the high driving force side boundary value FtHL according to the following equation (2).

FtHL = FtHLmax−α (2)
Here, α is a variable correction coefficient set so as to increase as the driving force change rate RFt increases. The ECU 100 holds in advance a correction coefficient map in which the driving force change rate RFt is associated with the correction coefficient α in the ROM. In step S103, the ECU 100 calculates the driving force change rate RFt calculated in step S102. One corresponding value is selected, and the high driving force side boundary value FtHL is set by subtracting from the upper limit value of the high driving force side boundary value FtHL described above. In addition, the setting aspect of the high driving force side boundary value FtHL is not limited to what is illustrated here.

  Returning to FIG. 5, when the switching condition is corrected, the ECU 100 determines whether or not the required driving force Ft corresponds to the selection condition for the continuously variable transmission mode (that is, whether or not it corresponds to the MG1 lock region) (step). S104). If the condition for selecting the continuously variable transmission mode is not satisfied (step S104: NO), the ECU 100 controls the drive of the brake mechanism 400 so that the motor generator MG1 is in a locked state (step S106). When step S106 is executed, the process returns to step S101. When MG1 is already in the locked state (that is, when the fixed speed change mode is continued), ECU 100 skips step S106 and returns the process to step S101.

  On the other hand, when the required driving force Ft satisfies the selection condition for the continuously variable transmission mode (step S104: YES), the ECU 100 further determines whether or not the fixed transmission mode is currently selected (step S105). At this time, if the continuously variable transmission mode is already selected at this time (step S105: NO), the ECU 100 returns the process to step S101.

  If it is determined in step S105 that the fixed transmission mode is currently selected (step S105: YES), that is, if it is necessary to switch the traveling mode from the fixed transmission mode to the continuously variable transmission mode, the ECU 100 Increases the intake air amount by the drive control of the throttle valve 208 and the accompanying increase in the fuel injection amount by the drive control of the injector 212, and the engine torque TE is consumed for the rotation increase of the motor generator MG1 in the stopped state. And the amount corresponding to the difference between the torque required for the drive shaft 302 and the current engine torque in accordance with the required driving force at that time (step S107).

  When the engine torque is increased, ECU 100 drives and controls brake mechanism 400 so that motor generator MG1 is unlocked (step S108). When motor generator MG1 is unlocked, the process returns to step S101. The traveling mode selection control is executed in this way. Note that the control of the output of each power source in each of the continuously variable transmission mode and the fixed transmission mode is appropriately executed by a separate control program for output control, and details thereof will not be described in the present embodiment.

<Effect of embodiment>
When the motor generator MG1 is set to the unlocked state in step S108 and the continuously variable transmission mode is selected, the target rotational speed of the motor generator MG1 is of course changed to zero according to the vehicle speed V and the required driving force Ft at that time. Therefore, a relatively large speed deviation up to the target rotational speed is generated transiently. However, in order to cause motor generator MG1 to shift from a state where the rotational speed is zero to a corresponding rotational state, so-called excessive torque that counters inertia of motor generator MG1 is required. In addition, since the required driving force itself can constantly change over time, if it further increases after the time when the switching of the traveling mode is required, the excess torque is also required.

  If this surplus torque cannot be procured, a part of the engine torque TE is consumed, for example, by the rotation increase of the motor generator MG1, and the torque of the drive shaft 302 that defines the drive force applied to each drive shaft is substantially reduced. As a result, the driving force supplied to each drive shaft decreases, and the power performance decreases transiently. According to the travel mode selection control according to the present embodiment, the engine torque is increased in step S107, so that the rotation speed of the motor generator MG1 can be increased without decreasing the output torque Tout of the drive shaft 302. It becomes.

  Here, in particular, when the engine torque TE is already the maximum torque TEmax when executing step S107, it is impossible to increase the engine torque. Therefore, in this embodiment, the travel that defines the travel mode switching conditions is performed. The high driving force side boundary value FtHL defined on the mode selection map is set according to a correction coefficient α that is variable according to the driving force change rate RFt (that is, the engine torque margin corresponding to the physical upper limit value). Is done. That is, the high driving force side boundary value FtHL is less than the upper limit value FtHLmax as long as the driving force change occurs, and the margin for outputting the above-described excessive torque is ensured. Therefore, according to the present embodiment, the shortage of driving force during the transition period in which the travel mode is switched from the fixed transmission mode to the continuously variable transmission mode is resolved, and the power performance of the hybrid vehicle 10 is ensured. That is, a decrease in drivability during the transition period is prevented.

  Here, in the same apparatus configuration as that of the present embodiment, when only this type of engine torque margin is considered and the high driving force side boundary value FtHL is set to a fixed value less than the upper limit value FtHLmax in advance, the above-described drivability is apparent. It seems that the benefits of preventing decline are enjoyed. However, in many cases, the required driving force Ft continuously changes when the travel mode is switched, and the magnitude of the required driving force Ft itself is in a wide range. Therefore, how much driving power margin is required depends on the driving conditions of the hybrid vehicle 10 at that time.

Therefore, if a margin is provided for the high driving force side boundary value FtHL in advance, if the change in the required driving force that occurs transiently is not taken into account, the decrease in drivability due to the lack of driving force is completely resolved after all. The high driving force side boundary value FtHL is not different from the case where the upper limit value FtHLmax is set. From another point of view, if you dislike drivability reduction due to insufficient driving force and set the margin larger than necessary, the fixed transmission mode itself will be difficult to continue. A decrease in efficiency becomes a separate problem. In this regard, as exemplified in the present embodiment, when the high driving force side boundary value FtHL is variable according to the required driving force change rate RFt, an appropriate margin according to the driving condition of the hybrid vehicle 10 is obtained. Setting is possible, and the improvement effect of the system efficiency by the fixed speed change mode can be maintained as much as possible while reliably preventing the drivability from being lowered due to insufficient driving force. That is, the technical idea according to the present invention is clearly superior to the technical idea that does not consider the change in the required driving force.
<Second Embodiment>
Next, a second embodiment of the present invention will be described. First, the configuration of the hybrid vehicle 20 according to the second embodiment will be described with reference to FIG. FIG. 7 is a schematic configuration diagram conceptually showing the configuration of the hybrid vehicle 20. In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In FIG. 7, the hybrid vehicle 20 is different from the hybrid vehicle 10 according to the first embodiment in that the ecological switch 15 is provided.

  The eco switch 15 is a button switch that is configured to be operable in the interior of the hybrid vehicle 20 and is an electric signal (that is, a main signal indicating that economic performance should be given priority over power performance when operated by an operator). An example of the “predetermined input corresponding to the fact that power performance is not required as compared with normal times” according to the invention occurs. The eco switch 15 is electrically connected to the ECU 100, and the electrical signal is referred to by the ECU 100 at a constant or indefinite period.

  Next, a travel mode selection map referred to in the travel mode selection control will be described with reference to FIG. FIG. 8 is a schematic diagram of a travel mode selection map that is referred to when the eco switch 15 is operated according to the second embodiment. In the figure, the same reference numerals are given to the same portions as those in FIG. 6, and the description thereof is omitted as appropriate.

  In FIG. 8, the travel mode selection map referred to when the eco switch 15 is operated includes the travel mode selection map according to the first embodiment, the low vehicle speed side boundary value VLL, the high vehicle speed side boundary value VHL, and the low drive. The force side boundary value FtLL is common, and only the high driving force side boundary value FtHL is different. That is, in the present embodiment, the high driving force side boundary value FtHL is defined by the following equation (3).

FtHL = FtHLmax−α ′ (3)
Here, α ′ is a correction coefficient similar to the correction coefficient α of the first embodiment, but the degree of change with respect to the driving force change rate RFt is different, and the driving force change rate is different from that of the first embodiment. The gradient of change with respect to RFt is set small. Accordingly, the high driving force side boundary value FtHL is set on the high driving force side as compared with the first embodiment. For example, the high driving force side boundary value FtHL when the driving force change rate RFt = RFt2 is FtHL3 ( FtHL3> FtHL1), and the high driving force side boundary value FtHL when the driving force change rate RFt = RFt1 is FtHL4 (FtHL4> FtHL2). That is, the MG1 lock area is larger than that in the first embodiment. When the eco switch 15 is not operated, the travel mode selection map is the same as that in the first embodiment.

  According to the present embodiment, when the eco switch 15 is operated, the MG1 lock region becomes relatively large in this way. When the eco switch 15 is operated, the driver gives priority to economic performance, and the driving operation itself conforms to that, so the margin of the high driving force side boundary value FtHL with respect to the driving force change rate RFt is the first margin. It can be smaller than the embodiment. Further, when the eco-switch 15 is operated, economic performance is required as compared with power performance. Therefore, even if the stagnation of the acceleration performance due to the lack of driving force occurs due to the reduction of the margin, that is the drivability. Will not lead to a decline. On the other hand, since the MG1 lock region is expanded in this way, the fixed speed change mode is continued more extensively than in the first embodiment, so that high economic performance is ensured by optimizing the system efficiency. It is.

  In the present embodiment, the eco switch 15 is exemplified. However, based on the same idea, for example, a snow mode (for example, a snow road or an icy road is selected, and slip, spin, or tire due to an excessive change in driving force is selected. Operation of various operation means that can make a judgment that the change rate of the required driving force is small at the time of operation, such as a travel mode that does not cause a lock or the like, or a cruise mode (a travel mode that maintains the vehicle speed at a target value). At times, the MG1 lock area may be enlarged.

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

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 a schematic view illustrating a cross-sectional configuration of an engine provided in the hybrid drive device of FIG. 2. FIG. 3 is an operation alignment chart for explaining an operation state of each part of the hybrid drive device of FIG. 2. It is a flowchart of the travel mode selection control performed by ECU. FIG. 6 is a schematic diagram of a travel mode selection map referred to in the travel mode selection control of FIG. 5. It is a schematic block diagram which represents notionally the structure of the hybrid vehicle which concerns on 2nd Embodiment of this invention. FIG. 8 is a schematic diagram of a travel mode selection map that is referred to when the ECU executes travel mode selection control in the hybrid vehicle of FIG. 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 20 ... Hybrid vehicle, 100 ... ECU, 200 ... Engine, 201 ... Cylinder, 203 ... Piston, 205 ... Crankshaft, 300 ... Power split mechanism, MG1 ... Motor generator, MG2 ... Motor generator, 400 ... Brake Mechanism, 500 ... Deceleration mechanism, 1000 ... Hybrid drive device.

Claims (4)

An internal combustion engine, a first electric motor, a second electric motor, a first rotary element connected to the internal combustion engine, differentially rotatable with each other, a second rotary element connected to the first electric motor, and an axle A power distribution means comprising a plurality of rotating elements including a third output element coupled to the output member and the second electric motor, and a state of the second rotating element between a non-rotatable locked state and an unlocked state And a shift ratio that is a ratio between the engine rotation speed of the internal combustion engine and the output rotation speed that is the rotation speed of the output member as a travel mode according to the state of the second rotation element. A control device for a hybrid vehicle capable of selecting a continuously variable transmission mode that is continuously variable and a fixed transmission mode in which the transmission ratio is fixed,
Specifying means for specifying the degree of change in the required driving force of the hybrid vehicle;
Setting means for setting the driving mode switching condition according to the specified degree of change;
Control means for switching the travel mode by controlling the locking means based on the set switching condition;
A control apparatus for a hybrid vehicle, comprising: The switching condition is defined such that the fixed speed change mode is selected when the required driving force is equal to or less than a predetermined upper limit value,
The control device for a hybrid vehicle according to claim 1, wherein the setting means sets the upper limit value so as to decrease as the specified degree of change increases. The setting means sets the upper limit value so as to be larger than a normal value when a predetermined input in which a degree of change in the required driving force is specified in advance is generated. The control device for a hybrid vehicle according to claim 2. The degree of change in the required driving force is a rate of change in the required driving force. The hybrid vehicle control device according to any one of claims 1 to 3.

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