JP5831359B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a technical field of a hybrid vehicle control device that controls a hybrid vehicle including a flywheel having a variable inertial mass on an engine shaft of an internal combustion engine.

  Various types of flywheel physical structures with variable inertial mass have been proposed. On the other hand, regarding the control of a flywheel having a variable inertial mass, for example, there is a flywheel device disclosed in Patent Document 1. According to this flywheel device, the time required for shifting can be shortened by reducing the moment of inertia of the flywheel during downshifting.

  Further, in a two-motor hybrid vehicle that connects an engine and two motors via a differential mechanism, when the electric power regeneration by the motor on the drive shaft side is restricted by the charge limit power Win and cannot be sufficiently performed, There has also been proposed a technique for reducing the remaining amount of power stored in the power storage means by pulling up the engine rotation with a motor on the engine side or driving various auxiliary machines (for example, see Patent Document 2).

  In addition, a power unit configured to be able to connect / disconnect a flywheel to / from an engine shaft has also been proposed that performs engine control in accordance with an abnormality related to connection / disconnection of a flywheel (see Patent Document 3).

JP 2009-085400 A JP 2005-002989 A JP 2007-315220 A

  In a hybrid vehicle, when a negative torque is required for the drive shaft, such as during deceleration, regenerative braking using the regenerative torque of the rotating electrical machine is suitably performed. At this time, when the SOC (State Of Charge) of the power storage means is sufficiently large, the regenerative power may exceed the charge limit power Win (meaning acceptable power) during deceleration regeneration by the motor on the drive shaft side. .

  In such a case, for example, in a two-motor hybrid vehicle as disclosed in Patent Document 2, as described in the document, for example, a rotating electrical machine different from the rotating electrical machine on the drive shaft side used for regenerative braking is used. It is possible to take measures to expand the charging limited power Win by the power consumption at.

  Here, as an aspect of power consumption in this rotating electrical machine, it is known to increase the engine speed of the internal combustion engine. More specifically, for example, a target value of the engine speed is determined in order to ensure the amount of power storage means side acceptance necessary for performing desired regenerative braking, and the rotating electrical machine is driven on the power running side. The engine speed is increased to this target value.

  On the other hand, such a measure for increasing the engine speed can suitably perform regenerative braking, but the engine speed greatly fluctuates during regenerative braking, and thus tends to deteriorate so-called NV (Noise and Vibration). Conventionally, control of a hybrid vehicle from such a viewpoint has not been proposed.

  That is, the conventional technique has a technical problem that it is difficult to sufficiently perform regenerative braking within the physical allowable range of the power storage means while suppressing the deterioration of NV. If the auxiliary machine is driven instead of increasing the engine speed, the NV will not deteriorate at first glance, but the power consumed by the auxiliary machine is the same as the power consumed when the engine speed is forcibly increased. Compared to the original, the contribution to the expansion of the charge limited power Win is not necessarily sufficient.

  The present invention has been made in view of the above-described technical problems, and is a hybrid vehicle control device capable of sufficiently performing regenerative braking within the physical allowable range of the power storage means while suppressing the deterioration of NV. It is an issue to provide.

In order to solve the above-described problems, a control apparatus for a hybrid vehicle according to the present invention includes an internal combustion engine, a flywheel attached to an engine shaft of the internal combustion engine and having a variable inertial mass, a first rotating electrical machine, and an axle. A second rotating electrical machine capable of inputting and outputting torque with a drive shaft connected to the engine, and a differential element including a rotating element connected to the engine shaft, the output shaft of the first rotating electrical machine and the drive shaft, respectively. Controlling a hybrid vehicle comprising a differential mechanism having a plurality of rotatable rotating elements and power storage means, and configured to be able to input and output electric power between the power storage means and the first and second rotating electrical machines. A control device for a hybrid vehicle, wherein the required driving force calculating means for calculating the required driving force of the drive shaft and regenerative braking by regenerative torque when the calculated required driving force is negative. The second time A target value for the engine speed of the internal combustion engine is calculated based on the regenerative control means for controlling the electric machine, and when the regenerative braking is performed, based on the regenerative power related to the regenerative braking and the charge limiting power of the power storage means. And a target value calculating means that consumes when the engine speed of the internal combustion engine is increased by changing the inertial mass of the flywheel to a high inertia side when the calculated target value is higher than the current value. And an inertial control means for increasing the generated electric power (claim 1).

  A differential mechanism according to the present invention includes a rotating element connected to or configured to be connectable to an internal combustion engine and first and second rotating electric machines capable of both power running and regeneration. For example, rotation including a plurality of rotatable rotating elements (that is, the rotating elements corresponding to each power element may be at least a part of the rotating elements provided in the power split mechanism, but not necessarily all). It takes the form of a planetary gear mechanism with two degrees of freedom.

  This differential mechanism is based on the differential action between the rotating elements, with respect to the drive shaft (directly the output shaft of the differential mechanism) connected to the axle, whether directly or indirectly. A part of the engine torque of the internal combustion engine can be transmitted. The second rotating electrical machine can input and output torque with the drive shaft, and the hybrid vehicle according to the present invention generates a part of the engine torque of the internal combustion engine and the torque of the second rotating electrical machine. It is possible to perform so-called hybrid traveling by controlling cooperatively.

  On the other hand, when a regenerative torque as a negative torque is supplied from the second rotating electrical machine to the drive shaft, a braking force can be applied to the hybrid vehicle. Power generation). In the control apparatus for a hybrid vehicle according to the present invention, the required drive force as the drive force required for the drive shaft calculated by the required drive force calculation means (note that the relationship between the drive force and the torque depends on the gear ratio and the tire. If other factors such as the diameter are determined, the relationship is unambiguous, and at least it is not necessary to distinguish between them to specify the present invention) is a negative value. Then, braking with power regeneration, that is, regenerative braking is performed.

  Here, in the hybrid vehicle control device according to the present invention, the target value calculation means calculates the target value of the engine speed of the internal combustion engine based on the regenerative power related to regenerative braking and the charge limiting power of the power storage means.

  The regenerative electric power during the regenerative braking period is stored in power storage means configured to be able to input and output power to and from the first and second rotating electrical machines. The power storage means is caused by SOC, battery temperature, and the like. There is charge limit power (acceptable power). If the regenerative power at the time of regenerative braking is limited by this charge limit power, regenerative braking cannot be performed sufficiently. Therefore, a target value for the engine speed is determined in order to increase the charge limit power by forcibly increasing the engine speed via the first rotating electrical machine. The target value of the engine speed calculated by the target value calculating means is higher than the engine speed at that time when the regenerative power conflicts with the charge limit power.

  Particularly in the hybrid vehicle control device according to the present invention, when the calculated target value is higher than the current value, that is, when the regenerative power at the time of regenerative braking violates the charge limit power, the inertia control means The inertial mass of the flywheel is changed to the high inertia side (the side on which the inertial mass increases). When the inertial mass of the flywheel changes to the high inertia side with respect to the inertial mass at that time, whether binary, stepwise, or continuous, measures to increase the engine speed by the first rotating electrical machine are taken. In the process, the electric power consumed when the engine speed is increased by a predetermined amount increases. That is, when the power consumption necessary for setting the charge limiting power of the power storage means to a desired value is determined, the increase range of the engine speed in the engine speed increase measure is when the inertia mass is on the low inertia side. Smaller than that.

  Therefore, according to the present invention, it is possible to suppress NV that greatly depends on the range of increase in the engine speed, and to realize suitable regenerative braking according to the state of the power storage means without making NV obvious. It can be done.

  In the flywheel according to the present invention, the inertial mass is variable in a binary, stepwise or continuous manner. The physical structure for making the inertial mass variable is not uniquely defined, and various known modes can be adopted. For example, the flywheel according to the present invention is realized by accommodating a magnetic fluid in a disk-like flywheel so as to be movable in the radial direction and changing the radial position of the magnetic fluid stepwise or continuously. May be. Or the structure which implement | achieves a high inertia by connecting a subwheel to a main wheel and low inertia by comprising a flywheel from a main wheel and a subwheel, and using only a main wheel may be sufficient.

  In another aspect of the hybrid vehicle control device according to the present invention, the inertial control means increases the variation range of the inertial mass of the flywheel as the deviation between the target value and the current value increases. ).

  The deviation between the target value and the current value uniquely corresponds to the deviation between the charge limited power and the regenerative power. That is, the larger the deviation between the target value and the current value, the larger the surplus amount of regenerative power with respect to the charge limited power.

  Therefore, by increasing the change range of the inertial mass according to the deviation between the target value of the engine speed and the current value, the sudden change of the inertial mass is suppressed as much as possible to realize more efficient regenerative braking. Can do.

  In this case, the flywheel preferably has a variable inertial mass in multiple stages. However, even in a configuration in which the inertial mass changes in a binary manner, the flywheel has a high inertia side when the deviation exceeds a predetermined value. This mode can be realized by taking measures such as changing the inertial mass.

  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 a schematic cross-sectional view conceptually showing a configuration of an engine in the hybrid drive device of FIG. 2. FIG. 3 is an operation alignment chart of the hybrid drive device of FIG. 2. 2 is a flowchart of flywheel control executed by an ECU in the hybrid vehicle of FIG. 1. It is a flowchart of the flywheel control which concerns on 2nd Embodiment of this invention.

<Embodiment of the Invention>
Hereinafter, various embodiments of the present invention will be described with reference to the drawings.

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

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

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

  The ECU 100 is one of “required driving force calculation means”, “regeneration control means”, “target value calculation means”, “stop control means”, “inertia control means”, and “rotational speed control means” according to the present invention. It is an integrated electronic control unit configured to function as an example, 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. This is a power control unit that includes an inverter (not shown) that can be supplied to the battery 12 and that can control input and output of power between the battery 12 and the motor generator MG1 and the motor generator MG2. The PCU 11 is electrically connected to the ECU 100, and its operation is controlled by the ECU 100.

  The battery 12 is a battery unit having 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 is an example of the “storage unit” according to the present invention.

  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.

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

  In FIG. 2, the hybrid drive device 10 includes an engine 200, a flywheel 300, an input shaft 400, a power split mechanism 500, an MG1 output shaft 600, a drive shaft 700, a motor generator MG1, a motor generator MG2, and a reduction gear 800.

  The engine 200 is a multi-cylinder gasoline engine that 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 1. Here, the detailed configuration of the engine 200 will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view conceptually showing the 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 has at least one cylinder, and heat energy generated when an air-fuel mixture containing various fuels such as gasoline, light oil or alcohol is burned inside the cylinder, For example, it is a concept that encompasses an engine that can be extracted as kinetic energy through appropriate physical or mechanical transmission means such as a piston, a connecting rod, and a crankshaft. 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 that occurs in response to the above is configured to be converted into the rotational motion of the crankshaft 205 as an example of the “engine shaft” according to the present invention via the connecting rod 204. A crank position sensor 206 capable of detecting a crank angle θcrk, which is the rotation angle of the crankshaft 205, is installed in the vicinity of the crankshaft 205. 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 a crank angle signal output from the crank position sensor 206. be able to.

  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.

  A three-way catalyst 216 is installed in the exhaust pipe 215. The three-way catalyst 216 substantially simultaneously performs an oxidation combustion reaction of CO (carbon monoxide) and HC (hydrocarbon) discharged from the engine 200 and a reduction reaction of NOx (nitrogen oxide) discharged from the engine 200. It is a known exhaust purification catalyst device configured to purify the exhaust of the engine 200 by advancing.

  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, respectively, and the detected air-fuel ratio and cooling water temperature are appropriately referred to by the ECU 100, respectively.

  On the other hand, on the upstream side of the intake port 210 in the intake pipe 207, a throttle valve 208 capable of adjusting the intake air amount 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 an 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. That is, the throttle valve 208 is configured as a part of an electronically controlled throttle.

  Returning to FIG. 2, the flywheel 300 is a substantially disc-shaped vibration suppressing device that is attached to the above-described crankshaft 205 and rotates integrally with the crankshaft 205. The disc-shaped main body of the flywheel 300 is formed with a plurality of cylindrical accommodating portions extending in an arc shape in the radial direction from the vicinity of the center, and the magnetic fluid is movably accommodated in the accommodating portion. Has been. The flywheel 300 has a built-in magnetic field generator that can generate a magnetic field for changing the position of the magnetic fluid in the longitudinal direction of the housing portion. According to the strength of the magnetic field generated by the magnetic field generator, The position of the magnetic fluid in the container is changed.

  The magnetic fluid accommodated in the accommodating portion has a mass. Therefore, when the position of the magnetic fluid in the accommodating portion changes, the inertial mass of the flywheel 300 changes. In other words, the flywheel 300 has a lower inertia (small inertia mass) as the magnetic fluid is closer to the center, and the flywheel 300 has higher inertia (inertia mass) as the magnetic fluid is closer to the outer peripheral surface. It becomes. The relationship between the inertial mass of the flywheel 300 and the magnitude of the magnetic field generated by the magnetic field generator is given experimentally and theoretically in advance. The magnetic field generator is electrically connected to the ECU 100 and is driven under the control of the ECU 100. Therefore, the ECU 100 can continuously and variably control the inertial mass of the flywheel 300 to a desired value.

  The flywheel 300 is an example of the “flywheel” according to the present invention, and particularly adopts a configuration in which the inertial mass is controlled by changing the position of the magnetic fluid. However, such a control mode of the inertial mass is merely an example. Various known configurations can be applied to the physical configuration of the flywheel that can change the inertial mass.

  Motor generator MG1 is a motor generator that is an example of the “first rotating electrical machine” 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 has a configuration. The motor generator MG2 is a motor generator that is an example of a “second rotating electrical machine” according to the present invention. Like the motor generator MG1, the motor generator MG2 converts a power running function that converts electrical energy into kinetic energy, and converts kinetic energy into electrical energy. It has a configuration with a regenerative function. The motor generators MG1 and MG2 are configured as, for example, three-phase synchronous motor generators. For example, the motor generators MG1 and MG2 include 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. Although it has the structure with which it comprises, it may have another structure.

  The power split mechanism 500 includes a sun gear S1 as an example of the “rotating element” according to the present invention provided at the center, and the “rotating element” according to the present invention concentrically provided on the outer periphery of the sun gear S1. An example of the ring gear R1, a plurality of pinion gears P1 disposed between the sun gear S1 and the ring gear R1 and revolving while rotating on the outer periphery of the sun gear S1, and the rotation shafts of the respective pinion gears are supported. This is a planetary gear mechanism having two degrees of freedom of rotation, which is an example of the “differential mechanism” according to the present invention, and includes the carrier C1 as another example of the “rotating element” according to the present invention.

  In power split device 500, sun gear S1 is fixed to MG1 output shaft 600 (connected to rotor RT of motor generator MG1), which is the output shaft of motor generator MG1, and the rotational speed thereof is the rotational speed of motor generator MG1. This is equivalent to the MG1 rotational speed Nmg1. The ring gear R1 is fixed to the drive shaft 700, and the rotation speed thereof is equivalent to the output rotation speed Nout that is the rotation speed of the drive shaft 700. Note that the rotor of motor generator MG2 is fixed to drive shaft 700, and output rotation speed Nout is equal to MG2 rotation speed Nmg2 which is the rotation speed of motor generator MG2. The carrier C1 is connected to an input shaft 400 connected to the crankshaft 205 of the engine 200, and the rotational speed thereof is equivalent to the engine rotational speed NE of the engine 200. In the hybrid drive device 10, the MG1 rotation speed Nmg1 and the MG2 rotation speed Nmg2 are detected at a constant cycle by a rotation sensor such as a resolver, and are sent to the ECU 100 at a constant or indefinite cycle.

  The drive shaft 700 includes drive shafts 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 1 (that is, these drive shafts are examples of the “axle” according to the present invention). It is connected via a reduction mechanism 800 as a reduction device including various reduction gears such as a differential. Accordingly, motor torque Tmg1 supplied to drive shaft 700 during powering of motor generator MG2 is transmitted to each drive shaft through reduction mechanism 800 and used as driving power for hybrid vehicle 1. On the other hand, the driving force input to drive shaft 700 via each drive shaft and speed reduction mechanism 800 during regeneration of motor generator MG2 is used as power for power generation of motor generator MG2. In this case, the motor torque Tmg1 of the motor generator MG2 is a kind of regenerative torque, and the magnitude thereof correlates with the magnitude of the regenerative power and the magnitude of the braking force (regenerative braking force) applied to the drive wheels via the drive shaft 700. To do. The MG2 rotational speed Nmg2 is uniquely related to the vehicle speed V of the hybrid vehicle 1.

  In the hybrid drive device 10, the power split mechanism 500 applies engine torque Te supplied from the engine 200 to the input shaft 400 via the crankshaft 205 to the sun gear S1 and the ring gear R1 by the carrier C1 and the pinion gear P1. It is possible to divide the power of the engine 200 into two systems by distributing at a ratio (a ratio according to the gear ratio between the gears). More specifically, 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 for easy understanding of the operation of the power split mechanism 500, the engine torque Te is set from the engine 200 to the carrier C1. When applied, the torque Tes appearing on the MG1 output shaft 600 is represented by the following equation (1), and the engine direct torque Tep appearing on the drive shaft 700 is represented by the following equation (2).

Tes = Te × ρ / (1 + ρ) (1)
Tep = Te × 1 / (1 + ρ) (2)
The configuration according to the embodiment relating to the “differential mechanism” according to the present invention is not limited to that illustrated as the power split mechanism 500. 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 800 according to the present embodiment merely reduces the rotational speed of the drive shaft 700 in accordance with a preset speed reduction ratio, but the hybrid vehicle 1 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.

<Operation of Embodiment>
<Operation of Power Split Mechanism 500>
In the hybrid vehicle 1 according to the present embodiment, a kind of electric CVT (Continuously Variable Transmission) function is realized by the differential action of the power split mechanism 500. Here, the operation of the power split mechanism 500 will be described with reference to FIG. FIG. 4 is an operation collinear diagram of the hybrid drive device 10. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof will be omitted as appropriate.

  In FIG. 4, the vertical axis represents the rotational speed, and the horizontal axis represents the motor generator MG1 (uniquely sun gear S1), engine 200 (uniquely carrier C1), and motor generator MG2 (uniquely) in order from the left. The ring gear R1) is represented.

  Here, the power split mechanism 500 is a planetary gear mechanism that exhibits a differential action of two degrees of freedom between rotating elements, and when the rotational speeds of two elements of the sun gear S1, the carrier C1, and the ring gear R1 are 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. It should be noted that the points on the operation collinear chart will be represented by operation points mi (i is a natural number) as appropriate. That is, one rotational speed corresponds to one operating point mi.

  In FIG. 4, it is assumed that the operating point of motor generator MG2 is operating point m1. In this case, if the operating point of motor generator MG1 is operating point m3, the operating point of engine 200 connected to carrier C1, which is the remaining one rotation element, is operating point m2. At this time, for example, if the operating point of the motor generator MG1 is changed to the operating point m4 and the operating point m5 while maintaining the rotational speed of the drive shaft 700, the operating point of the engine 200 is changed to the operating point m6 and the operating point m7, respectively. And change.

  That is, in hybrid drive device 10, engine 200 can be operated at a desired operating point by using motor generator MG1 as a rotational speed control device. The operating point of the engine 200 (the operating point in this case is defined by the combination of the engine speed and the engine torque Te) is basically the optimum fuel consumption operating point at which the fuel consumption rate of the engine 200 is minimized. Be controlled.

  In addition, to supplement, in order to supply the engine direct delivery torque Tep corresponding to the engine torque Te described above to the drive shaft 700 in the power split mechanism 500, the magnitude of the torque Tes that appears according to the engine torque Te and the magnitude thereof are described. Must be supplied to the MG1 output shaft 600 from the motor generator MG1. In this case, at the operating point in the positive rotation region such as the operating point m3 or the operating point m4, MG1 is in a power generation state of positive rotating negative torque. That is, in the hybrid drive device 10, the motor generator MG <b> 1 functions as a reaction force element, thereby generating power while supplying a part of the engine torque Te to the drive shaft 700. When drive shaft required torque Tpn, which is a torque required for drive shaft 700, is insufficient with engine direct torque Tep, motor torque Tmg2 is appropriately supplied to drive shaft 700 from motor generator MG2.

  On the other hand, when the vehicle needs a braking force, such as during vehicle deceleration, the vehicle can be decelerated by controlling the motor torque Tmg2 supplied from the motor generator MG2 to the drive shaft 700 to a negative torque. In this case, since motor generator MG2 has a negative torque in the positive rotation region, it enters a power regeneration state. That is, the negative motor torque Tmg2 is a regenerative torque, and is a torque for realizing so-called regenerative braking in which power regeneration is performed while applying a braking force to the vehicle.

  Here, at the time of regenerative braking, the regenerative power is determined by the magnitude of the regenerative torque and the MG2 rotational speed Nmg2 (uniquely the rotational speed of the drive shaft 700). is there. The degree of this restriction is expressed as charge restriction power Win, and changes appropriately depending on the SOC (State Of Charge) of the battery 12, the battery temperature, and the like. The charge limit power Win is repeatedly calculated at a predetermined cycle by the ECU 100 based on a known method. From the viewpoint of protecting the battery 12, it is not possible to supply the battery 12 with power exceeding the charging limit power Win, and in such a case, appropriate measures are required.

  As this type of countermeasure, it is conceivable to reduce the regenerative torque. However, if the regenerative torque is reduced, the braking force to be applied to the vehicle is reduced, so that the insufficient braking force needs to be replaced by friction braking force by various known hydraulic braking devices provided separately for the vehicle. In this case, there is no problem in the balance of braking force, but it is not always sufficient from the viewpoint of effectively using energy resources.

  Therefore, in the case where it is predicted that power regeneration exceeding the charge limit power Win will occur, the power is forcibly consumed by the motor generator MG1 to reduce the SOC of the battery 12, and thus the charge limit power Win. Measures will be taken to expand The power consumption by the motor generator MG1 means that the motor generator MG1 is operated in the positive rotation positive torque region, and as is clear from the operation alignment chart of FIG. Means to raise.

  However, when the engine speed NE is increased in this way, the NV in the hybrid vehicle 1 is deteriorated as the increase range of the engine speed is larger. Therefore, in the present embodiment, the ECU 100 executes flywheel control to suppress the increase range when the engine speed NE is forcibly increased.

<Details of flywheel control>
Here, with reference to FIG. 5, the flywheel control performed by ECU100 as operation | movement of this embodiment is demonstrated. FIG. 5 is a flowchart of the flywheel control. The flywheel control is control for maintaining the inertial mass of the flywheel 300 at an optimum value. Note that the flywheel control is one of various types of control executed when the ECU 100 controls the operation of the hybrid vehicle 1 and is repeatedly executed at a predetermined cycle.

  In FIG. 5, the ECU 100 calculates a required drive torque Tpn that is a torque required for the drive shaft 700 (step S110). The required drive torque Tpn is calculated by performing a predetermined conversion process on the required drive force Ft. The required driving force Ft is selected from the required driving force map stored in the ROM based on the accelerator opening degree Ta detected by the accelerator opening degree sensor 13 and the vehicle speed V detected by the vehicle speed sensor 14. Is obtained by

  When the required drive torque Tpn is calculated, the ECU 100 determines whether or not the calculated required drive torque Tpn is a negative value (step S120). Negative required drive torque Tpn corresponds to a request for deceleration of hybrid vehicle 1, and corresponds to a request for executing regenerative braking by supplying regenerative torque that is negative motor torque from motor generator MG2. When the required drive torque Tpn does not take a negative value (step S110: NO), that is, when it takes a positive value, the ECU 100 controls the inertial mass of the flywheel 300 in accordance with normal inertia control (step S190). The normal inertia control is a control for setting the inertial mass of the flywheel 300 to an optimum value in terms of operation control of the hybrid vehicle 1, which is experimentally, empirically or theoretically determined in advance. Since such normal inertia control has a low relationship with the present application, the details are omitted here. However, in this embodiment, the inertial mass of the flywheel 300 is controlled in a binary manner between a value on the low inertia side (side where the inertial mass is small) and a value on the high inertia side (side where the inertial mass is large). Shall be. The inertial mass of the flywheel 300 changes when the drive device of the flywheel 300 is driven and controlled in accordance with a command value (high inertia command value or low inertia command value) of the ECU 100.

  When the required drive torque Tpn is a negative value (step S120: YES), that is, when there is a request for execution of regenerative braking, the ECU 100 acquires the charge limiting power Win of the battery 12 (step S130). The charge limit power Win is the SOC value of the battery 12 that is separately acquired or estimated by the ECU 100 (for example, a value obtained by normalizing the charge state with 100% being fully charged and 0% being completely discharged) Based on the temperature or the like, it is acquired from the charge limit power map stored in the ROM. Charging limit power Win basically decreases stepwise as the SOC value approaches 100 (%).

  When acquiring the charge limit power Win, the ECU 100 calculates the target engine speed NEtg of the engine 200 from the required drive torque Tpn and the charge limit power Win (step S140). Here, the target engine speed NEtg calculated in step S140 is the current value if the regenerative power due to regenerative braking is less than the charge limit power Win, and if the regenerative power is greater than or equal to the charge limit power Win, depending on the deviation. Is set at a higher speed than the current value.

  Specifically, ECU 100 calculates regenerative power (generated power) when regenerative torque corresponding to required drive torque Tpn is supplied from motor generator MG2. This regenerative power is obtained by numerical calculation based on the magnitude of the regenerative torque and the MG2 rotational speed Nmg2. Next, a deviation (charging power deviation) between the regenerative power and charging limited power Win by the motor generator MG2 is calculated, and the target engine speed NEtg is set higher as the charging power deviation is larger.

  The target engine speed NEtg is a target of a forced increase measure of the engine speed NE by the motor generator MG1, and is necessary for enabling the regenerative torque corresponding to the required drive torque Tpn to be supplied to the drive shaft 700. It is determined based on the electric power (which increases as the charging power deviation increases) and the power consumption required for motor generator MG1 to increase the engine speed of engine 200 by a unit amount.

  The power consumption required for motor generator MG1 to increase the engine speed of engine 200 by a unit amount varies depending on the inertial mass of flywheel 300 attached to crankshaft 205. As described above, the inertial mass of the flywheel 300 is controlled to either the low inertia side or the high inertia side by the normal inertia control in step S190, and the ECU 100 determines the inertial mass of the flywheel 300 at that time. Based on the above, the power consumption is calculated, and the target engine speed NEtg is calculated.

  The ECU 100 determines whether or not the calculated target engine speed NEtg is higher than the current value (that is, the current engine speed NE) (step S150). If the rotation speed is not higher than the current value (step S150: NO), that is, if the regenerative power at the time of regenerative braking does not conflict with the charge limit power Win, the inertial mass of the flywheel 300 is maintained at the current value. (Step S180). On the other hand, when the calculated target engine speed NEtg is higher than the current value (step S150: YES), that is, when the regenerative power at the time of regenerative braking is in conflict with the charge limit power Win, the ECU 100 Then, it is determined whether or not a low inertia command is being executed for the flywheel 300 (step S160). If the high inertia command is in progress (step S160: NO), the process proceeds to step S180, and the inertial mass is maintained at the current value (that is, the value on the high inertia side).

  Here, when the regenerative electric power at the time of regenerative braking conflicts with the charging limit electric power Win and the low inertia command is being issued to the flywheel 300 (step S160: YES), the ECU 100 A high inertia command is executed (step S170). When the high inertia command is executed, the flywheel control ends.

  When the inertial mass of the flywheel 30 changes to a value on the high inertia side by this high inertia command, the power consumption when forcibly increasing the engine speed NE by driving the motor generator MG1 is referred in step S140. It increases compared to the consumed power. Therefore, when taking measures to increase the engine speed NE by the motor generator MG1 in parallel with the flywheel control, before the engine speed NE reaches the target engine speed NEtg set in step S140. The charging restriction by the charging restriction power Win is released. That is, the increase range of the engine speed NE is reduced, and the rotational fluctuation of the engine 200 is suppressed as much as possible. As a result, when the regenerative braking proceeds as expected, it is possible to suppress the deterioration of the NV in the hybrid vehicle 1 as much as possible.

  In the control mode in which the inertial mass of the flywheel 300 is switched in a binary manner as described above, diversity can be provided by a structure in which the inertial mass is variable in the flywheel 300.

Second Embodiment
Next, flywheel control according to a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a flowchart of flywheel control according to the second embodiment. In the figure, the same reference numerals are assigned to the same parts as those in FIG. 5, and the description thereof is omitted as appropriate.

  In FIG. 6, when the target engine speed NEtg is higher than the current value (step S150: YES) and a low inertia command is executed for the flywheel 300 (step S160: YES), the ECU 100 Then, the rotational speed deviation ΔNE is acquired (step S161). The rotational speed deviation ΔNE is a difference between the target engine rotational speed NEtg and the current value. When the rotational speed deviation ΔNE is acquired, the ECU 100 executes a multistage (or continuous) inertia command in accordance with the rotational speed deviation ΔNE (step S171). That is, if the rotational speed deviation ΔNE is large, an inertia command to the higher inertia side is issued.

  According to the present embodiment, since the inertial mass of the flywheel 300 is controlled according to the rotational speed deviation ΔNE, the change in the inertial mass of the flywheel 300 can be made within a range in which the deterioration of the NV of the hybrid vehicle 1 is not manifested. Can be suppressed. Therefore, there is no need to unnecessarily change the inertial mass of the flywheel 300, and energy resources for driving the flywheel 300 (in this embodiment, power resources for generating a magnetic field) are saved correspondingly. Can do.

  In this embodiment, normal inertia control (step S190) in the flywheel 300 is the same as that in the first embodiment. However, in view of the fact that the flywheel 300 has a configuration in which the inertial mass can be continuously and variably controlled, the inertial mass of the flywheel 300 is multistage in the normal inertial control corresponding to step S190 ( (Alternatively, it may be controlled). In this case, the determination process according to step S160 is a process for determining whether or not a command other than the high inertia command is being executed, and when branching to the “YES” side, the rotation is performed in the range of the remaining control width of the inertial mass. An inertia command may be issued according to the number deviation ΔNE.

  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.

  The present invention is applicable to a hybrid vehicle having a flywheel having a variable inertial mass.

  DESCRIPTION OF SYMBOLS 1 ... Hybrid vehicle, 10 ... Hybrid drive device, 100 ... ECU, 200 ... Engine, 300 ... Flywheel, 400 ... Input shaft, 500 ... Power split mechanism, 600 ... MG1 output shaft, 700 ... Drive shaft, 800 ... Deceleration mechanism , MG1, MG2 ... motor generators.

Claims (2)

An internal combustion engine;
A flywheel attached to the engine shaft of the internal combustion engine and having a variable inertial mass;
A first rotating electrical machine;
A second rotating electrical machine capable of torque input and output with a drive shaft connected to the axle;
A differential mechanism comprising a plurality of rotating elements capable of differentially rotating with each other, including rotating elements connected to the engine shaft, the output shaft of the first rotating electrical machine and the drive shaft, respectively;
Power storage means, and
A hybrid vehicle control device that controls a hybrid vehicle configured to be able to input and output electric power between the power storage means and the first and second rotating electrical machines,
Required driving force calculating means for calculating the required driving force of the drive shaft;
Regenerative control means for controlling the second rotating electrical machine so that regenerative braking by regenerative torque is performed when the calculated required driving force is negative;
Target value calculating means for calculating a target value of the engine speed of the internal combustion engine based on regenerative electric power related to the regenerative braking and charge limit power of the power storage means when the regenerative braking is performed;
When the calculated target value is higher than the present value, the inertial mass of the flywheel is changed to a high inertia side to increase the power consumed when the engine speed of the internal combustion engine is increased. A control device for a hybrid vehicle, comprising: control means. 2. The control apparatus for a hybrid vehicle according to claim 1, wherein the inertia control unit increases a change width of an inertial mass of the flywheel as the deviation between the target value and the current value increases.

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