JP2011063063A - Device for control of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve suitable fail-safe operation in failure of a changeover mechanism. <P>SOLUTION: A hybrid vehicle includes: an internal combustion engine (200); a power transmission mechanism (400); a first motor generator (MG1); a second motor generator (MG2) configured such that input/output of motive power is possible with a driving shaft (600); an energy storage means (12); and a lock mechanism (500) capable of selectively changing over a state of one rotary element (S2) equipped in the power transmission mechanism between a lock state and a non-lock state. The hybrid vehicle further includes: a decision means (100) for determining whether the lock mechanism is in a normal state of being able to change over a speed change mode to a continuously variable transmission mode from a fixed transmission mode; and a correction means (100) for correcting a power regeneration amount of the second motor generator to an increase side as compared with when the lock mechanism is in the normal state in a fail-safe operation request period wherein the lock mechanism is not in the normal state and wherein the fixed transmission mode is selected as the speed change mode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technical field of a hybrid vehicle control device that controls a hybrid vehicle having a mechanism for switching a gear ratio.

  An apparatus for controlling a hybrid vehicle that can realize a fixed gear ratio and a continuously variable gear ratio by a fastening element as a mechanism of this type has been proposed (see Patent Document 1). According to this device, when the fastening element falls into an ON failure (that is, a failure in which the fastening element cannot be released) or an OFF failure (that is, a failure in which the fastening element cannot be fastened), the substitute mode control unit executes the substitute mode. Thus, the vehicle can be driven.

  A vehicle configuration for switching between a fixed gear ratio and a continuously variable gear ratio is also disclosed in Patent Document 2.

  Patent Document 3 discloses an apparatus that starts a vehicle by a motor generator and starts the engine if the engine speed is equal to or higher than a predetermined speed when a clutch failure occurs in a series hybrid vehicle.

JP 2006-22844 A JP 2004-345527 A JP 2002-51407 A

  In a state where the fixed gear ratio is selected, when the switching mechanism responsible for switching the gear ratio fails (that is, a failure similar to the above-mentioned ON failure), the speed ratio is fixed, so that the rotation of the internal combustion engine Speed is directly affected by vehicle speed. This is not fundamentally changed when the alternative mode is selected as disclosed in Patent Document 1 above.

  On the other hand, even when the rotational speed of the internal combustion engine falls below a lower limit value at which stable rotation is possible due to a decrease in the vehicle speed, for example, as illustrated in Patent Document 3, the drive shaft connected to the axle is used. In a configuration including a power source such as a motor generator that can supply power independently, the hybrid vehicle can perform so-called EV traveling by supplying power from the power source.

  However, when the hybrid vehicle performs EV traveling, it is basically difficult to regenerate power other than during deceleration. Therefore, the SOC (State Of Charge) of the power storage means is defined as a state of charge that regulates the state of charge or the state of charge. It tends to decrease. Here, in such a state where the transmission gear ratio is fixed, the power required for starting the vehicle must be supplied from a power source other than the internal combustion engine. However, when the SOC of the power storage means is extremely insufficient, There is a possibility that the hybrid vehicle cannot start without being able to cover the power required for the vehicle.

  In other words, the conventional techniques exemplified in the various patent documents mentioned above have a technical problem that it is difficult to start the vehicle when the gear ratio switching mechanism is turned on.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for a hybrid vehicle that can realize a suitable fail-safe when a switching mechanism fails.

  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 rotation element, a second rotation element connected to a drive shaft connected to an axle, and a first rotation element connected to the internal combustion engine. A power transmission mechanism including a plurality of rotational elements including three rotational elements that are differentially rotatable with each other; a first motor generator coupled to the first rotational element and capable of adjusting a rotational speed of the internal combustion engine; A second motor / generator configured to be able to input / output power to / from the drive shaft, and functions as a power source for the first and second motor / generators, and the electric power in the first and second motor / generators The power storage means that can be charged by regeneration and the state of the one rotating element provided in the power transmission mechanism are configured to be selectively switchable between a non-rotatable locked state and a rotatable non-locked state, (1) The one rotation required In the non-locking state, the continuously variable transmission mode in which the speed ratio, which is the ratio between the rotational speed of the internal combustion engine and the rotational speed of the drive shaft, is continuously variable, and (2) the one rotation A device for controlling a hybrid vehicle including a lock mechanism capable of selecting a fixed transmission mode in which the transmission gear ratio is fixed by setting an element in the locked state as a transmission mode, wherein the lock mechanism is fixed. Determining means for determining whether or not the shift mode can be switched from the shift mode to the continuously variable shift mode; and determining whether the lock mechanism is not in the normal state and the fixed shift as the shift mode In the fail-safe request period in which the mode is selected, the power regeneration amount of the second motor generator is increased compared to the case where the lock mechanism is in the normal state. Characterized by comprising a correction means for correcting the.

  In the hybrid vehicle according to the present invention, as a power element capable of supplying power to the drive shaft, the physical, mechanical, or fuel type, fuel supply mode, fuel combustion mode, intake / exhaust system configuration, cylinder arrangement, etc. An internal combustion engine as an engine capable of generating power by combustion of fuel, which can take various modes regardless of electrical configuration, and various motor generators capable of powering and power generation (that is, power regeneration) A vehicle including at least a first motor generator and a second motor generator.

  The hybrid vehicle control device according to the present invention is a control device that controls such a hybrid vehicle, and includes, for example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units), various processors, or various controllers. Alternatively, various processing units such as a single or plural ECUs (Electronic Controlled Units), which may appropriately include various storage means such as ROM (Read Only Memory), RAM (Random Access Memory), buffer memory or flash memory Various computer systems such as various controllers or microcomputer devices can be used.

  The hybrid vehicle according to the present invention includes a power transmission mechanism. The power transmission mechanism includes a plurality of rotating elements capable of performing a differential action with respect to each other, including a first rotating element, a second rotating element connected to the drive shaft, and a third rotating element connected to the internal combustion engine. Due to such differential action, each rotating element is in a state (including whether or not it is rotatable and whether or not it is connected to another rotating element or a fixed element). It is a mechanism that enables various types of power transmission (terminally torque transmission) between the power element and the drive shaft. As a preferred embodiment, the power transmission mechanism can include one or a plurality of differential gear mechanisms such as a planetary gear mechanism. When a plurality of planetary gear mechanisms are included, each planetary gear mechanism is configured. A part of the rotating element can be appropriately shared among the plurality of planetary gear mechanisms.

  Here, the 1st motor generator as a motive power element is connected with this 1st rotation element, and is constituted so that adjustment of the revolving speed of an internal-combustion engine is possible. More specifically, at least the first, second, and third rotating elements of the plurality of rotating elements provided in the power transmission mechanism are naturally or selectively once the rotational speeds of the two elements are determined. A differential mechanism having two degrees of freedom of rotation in which the rotation speed of the remaining one rotation element is determined (note that the rotation elements included in this differential mechanism are not necessarily limited to these three elements). In such a configuration, the second rotating element connected to the drive shaft can be unique regardless of the vehicle speed, one-to-one, one-to-many, many-to-one, or many-to-many. By controlling the rotational speed of the elements, it is possible to adjust the rotational speed of the internal combustion engine. Further, in this case, the first motor generator can function as a reaction force element that applies reaction force torque to the internal combustion engine.

  On the other hand, the second motor generator is connected to the second rotating element connected to the drive shaft directly or indirectly through a speed change mechanism, a speed reduction mechanism, or the like. Therefore, the second motor generator can input and output power (in short, torque) with the drive shaft. For example, when power is input through a power transmission path that sequentially passes through the drive wheels, the axle, and the drive shaft, for example, in the positive rotation region, the second motor generator uses the input power as electric power. Regeneration, that is, power generation is possible.

  In the hybrid vehicle according to the present invention, the state of one of the rotating elements provided in the power transmission mechanism (hereinafter referred to as “locking target rotating element” as appropriate) is, for example, physical, mechanical, electrical, or magnetic. At least substantially the influence of the engagement force relating to this locked state and the non-rotatable locked state fixed to the predetermined fixing element so as not to rotate by various engagement forces (for example, hydraulic engagement force or electromagnetic engagement force). A lock mechanism that can take various modes such as a wet multi-plate brake device or a clutch device, an electromagnetic dog clutch device, or an electromagnetic cam lock type clutch device, which can be switched between a non-rotatable state and a non-rotatable state. Prepare. In the hybrid vehicle according to the present invention, the locked state and the non-locked state related to the lock target rotating element are configured to correspond to a fixed transmission mode and a continuously variable transmission mode as mutually different transmission modes.

  In the continuously variable transmission mode, the first motor generator functions as a rotation speed control mechanism of the internal combustion engine in the above-described two-degree-of-freedom differential mechanism, so that the rotation speed of the internal combustion engine and the rotation speed of the drive shaft are reduced. The gear ratio is theoretically, substantially or within a pre-defined physical, mechanical, mechanical or electrical constraint (steps equivalent to continuous in practice) This is a shift mode that can be changed.

  In this case, as a preferred embodiment, 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 speed and torque) is, for example, theoretically, substantially or It is freely selected within a range of constraints, for example, the fuel consumption rate is theoretically, substantially or minimally within a range of constraints, or the system efficiency of the hybrid vehicle (for example, the transmission efficiency of the power transmission mechanism and the internal combustion engine). The total efficiency calculated based on the thermal efficiency of the engine or the like) can theoretically be controlled to an optimum fuel consumption operating point or the like that is substantially or maximum within a range of some constraints.

  On the other hand, the fixed speed change mode is a speed change mode in which the speed ratio is uniquely defined, which is realized by maintaining the lock target rotating element in the locked state in the differential mechanism having two degrees of rotation. That is, when the rotation target rotation element is in the locked state, the remaining rotation depends on the rotation speed of the rotation target rotation element (that is, zero) and the rotation speed of the second rotation element that has a unique rotation state. The rotational speed of the third rotating element, which is at least one of the elements, is uniquely defined, and the rotational speed of the internal combustion engine converges to this uniquely defined value.

  At this time, if the lock target rotation element is the first rotation element, the first motor generator is rotated at zero rotation, and a so-called MG1 lock state or the like is realized. Further, if the rotation target rotation element is a rotation element that is different from the first, second, and third rotation elements and has a differential relationship with them, the rotation speed of the first motor generator is determined by the gear between them. It is fixed at one value determined according to the ratio. In the latter, preferably, a so-called O / D lock state in which the rotational speed of the internal combustion engine is less than the rotational speed of the drive shaft can be realized. In any case, in the fixed speed change mode, the rotational speed of the first motor generator loses the degree of freedom, and the reaction force torque can be applied from the engagement element related to the lock mechanism. It is no longer necessary to function as a reaction force element. Therefore, it is possible to avoid the generation of an inefficient electric path, which is called power circulation or the like, which can reduce the system efficiency of the entire hybrid drive device including the power element and the power transmission mechanism.

  Here, the locking mechanism according to the present invention locks the rotation target rotating element by applying a kind of engaging force between the engaging elements, whether physically, mechanically, electrically or magnetically. The structure which maintains in a state is taken. Therefore, switching between the locked and unlocked states works well enough to be practically negligible due to various physical, mechanical, electrical or magnetic reasons, for example. There are times when it stops.

  In particular, when it is difficult to switch from the locked state to the non-locked state (that is, a so-called ON failure, for example, the engagement elements are brought into contact with each other by frictional force, adhesion or fixation, partial biting, or electric (Including the case where the engagement elements are maintained in a relationship in which the engagement force exerts the engagement force due to inadequate mechanical or magnetic operation mechanism (for example, the electromagnetic force of the electromagnetic actuator cannot be controlled)). Since it is substantially fixed in the fixed speed change mode, it is easy to manifest as a problem that is difficult to overlook in practice compared to a case where switching from the non-locked state to the locked state is impossible (that is, a so-called OFF failure).

  For example, in the internal combustion engine, a lower limit value of a rotational speed that prescribes a rotational range in which stable rotation or self-rotation can be performed can be set in advance, but when the rotational speed of the internal combustion engine is unambiguous with respect to the vehicle speed, such There is a concern that the rotational speed of the internal combustion engine may be reduced regardless of this limitation. Such a problem relating to the rotational speed of the internal combustion engine is that the driving mode of the hybrid vehicle selected under the fixed speed change mode is changed from the HV mode in which a plurality of power elements can function as a power source, and only the second motor generator is used. This can be avoided by switching to the EV mode that functions as a power source. However, since the EV mode basically requires taking out the power from the power storage means, the power balance with respect to the power storage means tends to be negative, and the power storage means The SOC tends to decrease. In addition, the HV mode under the fixed speed change mode does not have such an unforeseen situation in mind, and the second motor generator is stopped or ensures the driving power of the electrical equipment. There is also an aspect that only a relatively small-scale power regeneration is performed.

  Here, in particular, when the hybrid vehicle stops in a state where the lock target rotation element is locked by the lock mechanism, it is difficult to start and rotate the internal combustion engine (that is, cranking), and the power from the second motor The supply requires the vehicle to start. However, in the situation where EV driving is continuously selected from the beginning, the amount of power taken out from the power storage means tends to increase, so that when the start request is made, the SOC of the power storage means is sufficiently secured. There is no guarantee. Therefore, when the lock mechanism is not in a normal state (that is, when it is difficult to shift the lock target rotation element to the non-lock state), it may be difficult to restart the hybrid vehicle once stopped. .

  Therefore, the control apparatus for a hybrid vehicle according to the present invention includes a determination unit and a correction unit. The determination unit determines whether or not the lock mechanism is in a normal state and determines that the lock mechanism is not in a normal state. In this case, the correction means determines that the power regeneration amount of the second motor generator is in the lock mechanism during the fail safe request period as a period in which it is determined that the lock mechanism is not in a normal state and the fixed speed change mode is selected. It is the structure which correct | amends to the increase side compared with the case where is in a normal state.

  Here, the practical aspect in which the correction means corrects the power regeneration amount of the second motor generator to the increase side is as long as the power necessary for restarting the hybrid vehicle can be secured in the fail-safe request period. In other words, it is possible to exceed the technical scope generally conceived from the phrase “amount of power regeneration”. That is, “correcting the power regeneration amount to the increase side” means increasing the power regeneration amount per unit time by increasing the directly achieved amount (direct torque) appearing on the drive shaft of the output torque of the internal combustion engine. In addition to the pure meaning such as, the meaning of resetting the final power storage target of the power storage means to a higher side (in this case, the total power regeneration amount increases), or the electric power by the second motor generator It preferably includes the meaning of expanding the operation range in which regeneration is performed (in this case, the power regeneration frequency increases).

  Therefore, according to the hybrid vehicle control device of the present invention, it is possible to reliably and reliably prevent a situation in which it is difficult to restart the hybrid vehicle due to the fact that the amount of power stored in the power storage unit is not secured. Therefore, a suitable fail safe when the lock mechanism is not in a normal state is realized.

  Supplementally, in the hybrid vehicle control device according to the present invention, the lock mechanism is not in a normal state (a state in which the lock target rotating element can be shifted from the locked state to the non-locked state), and the fixed transmission mode is selected. (I.e., the discriminating operation itself relating to the discriminating means may theoretically be performed at any timing, for example, as part of the start control when the IG is on, and the transition to the fixed shift mode is performed. If it is possible to obtain a determination that the lock mechanism is not in the normal state before, it is possible to simply take measures such as prohibiting the shift to the fixed transmission mode). We have found that there is a possibility that the power storage means may fall into power shortage, and in this fail-safe request period, it is required to restart the vehicle. The technical idea of the effect of correcting the power regeneration amount of the second motor-generator set, is obtained by allowing an accurate power securing storage means. In other words, unless the above problems are conceived, it is not easy to find the technical significance of quickly recovering or raising the SOC of the power storage means compared to the normal time during the fail-safe request period. This is because the amount of power regeneration of the second motor generator when the locking mechanism is in a normal state is also optimized, for example, experimentally, empirically, theoretically or based on simulation Because it is of nature.

  In one aspect of the hybrid vehicle control device according to the present invention, the hybrid vehicle further includes first control means for controlling the power regeneration amount based on a predetermined regeneration condition, and the correction means includes (1) the power storage means. At least one of the target charge amount, (2) the power regeneration amount per time, and (3) the power regeneration frequency of the second motor generator is corrected, and the first control means sets the correction as the regeneration condition. The power regeneration amount is controlled based on at least one of the generated values.

  According to this aspect, the first control means defines the regenerative conditions to be referred to when controlling the power regeneration amount of the second motor generator, the target charge amount of the power storage means, the power regeneration amount per hour, and the power regeneration frequency. At least one of them is corrected.

  The target charge amount of the power storage means is preferably a convergence target value of the feedback control of the SOC executed by the first control means, and the correction means is, for example, a normal SOC upper limit value defined for control of the power storage means The target value is corrected so as to be higher (for example, about 90%) (for example, about 70 to 80% with full charge as 100%). In this case, even if the power regeneration frequency and the amount of power regeneration per hour are the same as in normal times, it is possible to finally secure more power. On the other hand, the power regeneration amount per hour and the power regeneration frequency are mainly related to the charging speed of the power storage means, so that even if the target charge amount of the power storage means is the same as normal, the SOC of the power storage means is recovered quickly. Obviously, it is possible to secure a large amount of electric power as compared with the case where no measures are taken.

  In any case, these are corrected by a relatively light load process such as rewriting or switching at least part of an algorithm, an arithmetic expression, or a control map that is referred to when the first control unit controls the power regeneration amount. This is extremely reasonable and useful in that it is possible to more easily enjoy the practical benefits of the present invention.

  In another aspect of the hybrid vehicle control device according to the present invention, the hybrid vehicle further includes notification means for notifying the driver that the lock mechanism is not in the normal state.

  According to this aspect, the fact that the lock mechanism is not in a normal state is visually and audibly informed to the driver by the notification means that may have various aspects such as a display device, a voice guidance device, an alarm device, or a warning light. Or in a tactile manner or in a composite state. Therefore, on the driver side, it is not necessary to feel uncomfortable with respect to the point that the hybrid vehicle can take a different driving mode from the normal time due to the lock mechanism not being in a normal state, and a decrease in drivability is effectively suppressed. The In addition, in this way, by obtaining information about vehicle malfunctions that the driver cannot normally know, the driver can drive in consideration of that point, and can obtain a more suitable fail-safe It becomes.

  In another aspect of the control apparatus for a hybrid vehicle according to the present invention, the hybrid vehicle has, as a travel mode, an EV travel mode in which the required drive force of the hybrid vehicle is provided by power supply from the second electric motor to the drive shaft. The hybrid vehicle control device is capable of stopping the engine operation of the internal combustion engine when the rotational speed of the internal combustion engine is equal to or lower than a lower limit value during the fail-safe request period; And a second control unit that controls the second motor generator so that the travel mode is switched to the EV travel mode when the vehicle stops.

  According to this aspect, the engine operation of the internal combustion engine is stopped by the stop means when the rotational speed of the internal combustion engine is equal to or lower than the lower limit value during the fail safe request period. For this reason, misfire, vibration, noise, emission deterioration, and the like due to the forced operation of the internal combustion engine in the rotation region below the lower limit value are avoided, which is preferable. On the other hand, according to this aspect, the second control means switches the travel mode to the EV travel mode, so that deficiency in driving force due to the engine operation of the internal combustion engine being stopped in this way is suppressed, and the travel performance of the hybrid vehicle A decrease in drivability due to a decrease in the level of the problem is also suppressed.

  In one aspect of the hybrid vehicle control device according to the present invention including the second control means, the rotation speed of the internal combustion engine reaches a reference value greater than the lower limit value after the engine operation stops, or the internal combustion engine When the rotational speed continues and stays in a rotational speed range that is larger than the lower limit value, the engine further includes a starting means for restarting the internal combustion engine.

  The execution of the EV travel mode during the fail-safe request period has the effect of turning the power balance of the power storage means to the negative side, and is not necessarily preferable from the viewpoint of securing power when the vehicle restarts. On the other hand, when the above lower limit value is used as a reference for defining the start and stop timings of the internal combustion engine, the hybrid vehicle can operate in a speed range in which the rotational speed of the internal combustion engine fluctuates up and down across the lower limit value. When the vehicle is running, the internal combustion engine repeats engine stop and restart. Such an increase in the starting frequency of the internal combustion engine is undesirable from the viewpoints of drivability and energy consumption efficiency.

  In that respect, in this aspect, the starting means has an appropriate dwell time in a rotational speed range in which the rotational speed of the internal combustion engine reaches a reference value greater than the lower limit value or the rotational speed of the internal combustion engine is greater than the lower limit value. Since the internal combustion engine is restarted when the engine is stagnant, it is possible to suppress power consumption in the second motor generator as much as possible while suppressing an increase in the start frequency of the internal combustion engine.

  In this aspect, the engine further includes third control means for controlling the first motor / generator so as to suppress vibration generated when the internal combustion engine is restarted when the internal combustion engine is restarted. Also good.

  In this case, the third control means supplies a so-called damping torque (for example, a vibration having the internal combustion engine as a vibration source and a torque whose phase is reversed on the time axis) from the first motor generator, and restarts the internal combustion engine. Since the physical vibration at the time of making it suppress is suppressed, it becomes possible to perform restart of an internal combustion engine smoothly.

  In another aspect of the hybrid vehicle control device according to the present invention including the second control means, the determination means determines whether or not the lock mechanism is in the normal state at a predetermined cycle, and controls the hybrid vehicle. The apparatus further includes switching means for switching the shift mode to the continuously variable transmission mode when it is determined that the lock mechanism has returned to the normal state when the EV travel mode is selected as the travel mode. To do.

  According to this aspect, the determination means repeats the determination regarding whether or not the lock mechanism is in a normal state periodically (note that the period is not necessarily limited to the constant interval). When it is determined that the lock mechanism has returned to the normal state, the shift mode is quickly switched to the continuously variable transmission mode by the switching means. For this reason, it becomes possible to suppress the fall of the electrical storage amount of an electrical storage means as much as possible.

  In another aspect of the hybrid vehicle control device according to the present invention, switching the shift mode from the continuously variable shift mode to the fixed shift mode is prohibited when it is determined that the lock mechanism is not in the normal state. A prohibition unit is further provided.

  According to this aspect, when it is determined that the lock mechanism is not in the normal state, switching of the transmission mode from the continuously variable transmission mode to the fixed transmission mode is prohibited by the prohibiting unit. Therefore, even if it is determined that the lock mechanism is not in the normal state before the shift to the fixed speed change mode, or if the lock mechanism that is not in the normal state returns to the normal state for some reason, the lock mechanism is released again. A situation of shifting to an impossible state is prevented, and a suitable failsafe is realized.

  In another aspect of the hybrid vehicle control device according to the present invention, when the hybrid vehicle is requested to travel backward during the fail-safe request period, the hybrid vehicle further includes a limiting unit that limits the vehicle speed of the hybrid vehicle to a predetermined value or less. It has.

  In the fail-safe period, the reverse traveling is performed by supplying power from the second motor generator in a state where the lock target rotating element is locked. In this case, the internal combustion engine is operated in the reverse direction due to the configuration of the power transmission mechanism. Forced to rotate. According to this aspect, when reverse travel is requested during the fail-safe request period, the vehicle speed of the hybrid vehicle is limited to a predetermined value or less by the prohibiting means, so that the internal combustion engine does not fall into an excessive reverse rotation state. Thus, it is possible to reduce the burden on the hybrid vehicle.

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

1 is a schematic configuration diagram conceptually illustrating a configuration of a hybrid vehicle according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram conceptually showing a configuration of a hybrid drive device in the hybrid vehicle of FIG. 1. FIG. 3 is an operation alignment chart illustrating one operation state of the hybrid drive device of FIG. 2. 3 is a flowchart of fail-safe control executed by an ECU in the hybrid vehicle of FIG.

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

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

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

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM, and the like, and is configured to be able to control the operation of each part of the hybrid vehicle 1. It is an example of a “control device for a hybrid vehicle”. The ECU 100 is configured to execute fail-safe control described later according to a control program stored in the ROM. Note that the ECU 100 includes the “determination means”, “correction means”, “first control means”, “notification means”, “stop means”, “second control means”, “starting means”, “first” according to the present invention. 3 is an integrated electronic control unit configured to function as an example of each of “control means”, “switching means”, “prohibition means”, and “restriction means”, and all the operations related to these means are executed by the ECU 100. It is configured to be. 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 has a configuration in which a plurality of unit battery cells are connected in series, and is a battery unit that functions as a power supply source related to power for powering the motor generator MG1 and the motor generator MG2. It is an example of “means”.

  The accelerator opening sensor 13 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 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.

  The MIL (Multi Information Lump) 15 is an indicator constructed on the meter panel of the hybrid vehicle 1. MIL15 is comprised so that the information regarding the state of the hybrid vehicle 1 can be alert | reported visually with respect to a driver. The MIL 15 is configured to be driven and controlled by the ECU 100, and constitutes an example of the “notification unit” according to the present invention together with the ECU 100. The MIL 15 can display information indicating whether or not the lock mechanism 500 is in a normal state as part of its function. This information is appropriately utilized in fail-safe control described later.

  The MIL 15 is merely an example of a practical aspect of the notification means according to the present invention, and the notification means according to the present invention is incidental to the car navigation device when the hybrid vehicle 1 is provided with a car navigation device, for example. It may be a display device. Moreover, not only a display apparatus but various voice guidance apparatuses, an alarm apparatus, an alarm apparatus, etc. may be sufficient.

  In particular, when it is possible to give information to the driver using a partial function of the car navigation device, in addition to notifying that the lock mechanism 500 described later is not in a normal state, a resonance band unique to the hybrid vehicle 1 is obtained. Information related to (for example, the resonance band of the drive system in a low vehicle speed range of about 20 km / h) may be provided to the driver. In this case, drivability can be improved by encouraging the driver to prepare psychologically.

  The hybrid drive device 10 is a power unit that functions as a power train of the hybrid vehicle 1. A drive shaft 600 as a power output shaft of the hybrid drive device 10 (that is, an example of a “drive shaft” according to the present invention) is connected to a left front wheel FL and a right front wheel FR as drive wheels via a differential DG, respectively. The left axle SFL and the right axle SFR are connected. Therefore, the output rotational speed Nout, which is the rotational speed of the drive shaft 600, has a unique relationship with the vehicle speed V of the hybrid vehicle 10.

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

  In FIG. 2, the hybrid drive apparatus 10 includes an engine 200, a power split mechanism 400, a motor generator MG1 (hereinafter abbreviated as “MG1” as appropriate), a motor generator MG2 (hereinafter abbreviated as “MG2” as appropriate), a lock mechanism. 500 and MG2 transmission mechanism 600.

  The engine 200 is an in-line four-cylinder gasoline engine that is configured to function as a main power source of the hybrid vehicle 1 and that is an example of the “internal combustion engine” according to the present invention. The engine 200 is a known gasoline engine, and a detailed configuration thereof is omitted here, but the engine torque Te, which is the output power of the engine 200, is input to the input shaft 300 of the hybrid drive device 10 via a crankshaft (not shown). It is connected to. The engine 200 is merely an example of a practical aspect that can be adopted by the internal combustion engine according to the present invention. The practical aspect of the internal combustion engine according to the present invention is not limited to the engine 200, and various known engines can be employed. It is.

  Motor generator MG1 is a motor generator that is an example of the “first motor generator” 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 becomes the composition. The motor generator MG2 is a motor generator that is an example of the “second motor generator” according to the present invention and that is larger than the motor generator MG1. Like the motor generator MG1, the motor generator MG2 is a power running that converts electrical energy into kinetic energy. It has a configuration including a function and a regenerative function for converting kinetic energy into electrical energy.

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

  The power split mechanism 400 is a composite planetary gear mechanism that is an example of a “power transmission mechanism” according to the present invention, in which a first planetary gear mechanism and a second planetary gear mechanism are combined.

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

  The second planetary gear mechanism is disposed between the sun gear S2 provided in the center, the ring gear R2 provided concentrically on the outer periphery of the sun gear S2, and the sun gear S2 between the sun gear S2 and the ring gear R2. A plurality of pinion gears (not shown) that revolve while rotating around the outer periphery of the motor, and a carrier C2 that supports the rotation shaft of each pinion gear.

  Here, the ring gear R2 and the carrier C2 of the second planetary gear mechanism are directly connected to the carrier C1 and the ring gear R1 of the first planetary gear mechanism, respectively. Therefore, the ring gear R2 functions as an example of the “third rotating element” according to the present invention together with the carrier C1, and the carrier C2 functions as an example of the “second rotating element” according to the present invention together with the ring gear R1. .

  On the other hand, the sun gear S2 of the second planetary gear mechanism is connected to a lock mechanism 500, which will be described later, and can be selectively switched between a locked state and an unlocked state by the action of the lock mechanism 500. ing. That is, the sun gear S2 is an example of “one rotation element” according to the present invention, that is, a lock target rotation element. Each of the gears provided in the power split mechanism 400 has a differential relationship with each other, and constitutes an example of the “rotating element” according to the present invention.

  Here, the sun gear S1 is coupled to the rotor of the motor generator MG1 so as to share the rotation axis thereof, and the rotation speed thereof is equivalent to the MG1 rotation speed Nmg1 that is the rotation speed of the MG1. Ring gear R1 is connected to the rotor of motor generator MG2 via drive shaft 600 and MG2 speed change mechanism 700 described above, and the rotation speed thereof is equivalent to output rotation speed Nout described above. Further, the carrier C1 is connected to an input shaft 300 that is connected to the crankshaft of the engine 200, and the rotational speed thereof is equivalent to the engine rotational speed Ne of the engine 200.

  The MG2 speed change mechanism 700 is a stepped speed change mechanism interposed between the drive shaft 600 and the motor generator MG2. MG2 speed change mechanism 700 can change the rotational speed ratio between drive shaft 600 and motor generator MG2 in accordance with the gear ratio of the speed selected at that time. However, in this embodiment, the gear position of MG2 speed change mechanism 700 is fixed, and MG2 rotation speed Nmg2 that is the rotation speed of motor generator MG2 is uniquely related to output rotation speed Nout. . That is, the MG2 rotational speed Nmg2 is uniquely related to the vehicle speed V of the hybrid vehicle 1.

  Unlike motor generator MG1 and engine 200, motor generator MG2 can directly apply motor torque Tm2 that is its output torque to drive shaft 600. Therefore, motor generator MG2 can add torque to drive shaft 600 to assist the travel of hybrid vehicle 1 or can perform power regeneration by inputting torque from drive shaft 600.

  In the hybrid drive device 10, a rotation sensor such as a resolver is attached to a portion corresponding to the broken line frames A1, A2, and A3 shown in the figure, so that the rotation speed of the detection portion can be detected. These rotation sensors are in a state of being electrically connected to the ECU 100, and the detected rotation speed is sent to the ECU 100 at a constant or indefinite period. Supplementally, the rotational speed of the part corresponding to the illustrated broken line frame A1 is the above-described MG1 rotational speed Nmg1, and the rotational speed of the part corresponding to the illustrated broken line frame A3 is the above-described MG2 rotational speed Nmg2. . Moreover, the rotational speed of the broken line frame A2 shown in the figure is equivalent to the rotational speed of the sun gear S2, and this is referred to when controlling the operation of the lock mechanism 500.

  In the power split mechanism 400, the engine torque Te supplied from the engine 200 to the input shaft 300 is transferred to the sun gear S1 and the ring gear R1 by the carrier C1 with the predetermined ratio (the gear ratio between the gears). It is possible to divide the power of the engine 200 into two systems. At this time, in order to make the operation of the power split mechanism 400 easy to understand, when the gear ratio ρ as the number of teeth of the sun gear S1 with respect to the number of teeth of the ring gear R1 is defined, the engine torque Te is applied from the engine 200 to the carrier C1. In this case, the torque Tes acting on the sun gear S1 is expressed by the following equation (1), and the direct torque Ter appearing on the drive shaft 600 is expressed by the following equation (2).

Tes = −Te × ρ / (1 + ρ) (1)
Ter = Te × 1 / (1 + ρ) (2)
The configuration of the embodiment relating to the “power transmission mechanism” according to the present invention is not limited to that of the power split mechanism 400. For example, the power transmission mechanism according to the present invention may include only one planetary gear mechanism similar to the first planetary gear mechanism or the second planetary gear mechanism described above. In this case, for example, the sun gear S1 (S2) is connected to the MG1, the carrier C1 (C2) is connected to the engine 200, the ring gear R1 (R2) is connected to the drive shaft 600, and the sun gear S1 (S2) is connected to the lock mechanism 500. By being connected, the rotation operation of motor generator MG1 may be directly locked. Further, instead of the MG2 speed change mechanism 700, a planetary gear mechanism similar to the first or second planetary gear mechanism is interposed between the motor generator MG2 and the drive shaft 600. For example, the rotor of the MG2 is disposed in the sun gear of the planetary gear mechanism. The ring gear R1 may be coupled to the ring gear, and the carrier may be fixed to be non-rotatable to reduce the MG2 rotational speed Nmg2 with respect to the output rotational speed Nout.

  The lock mechanism 500 includes a hub 501, an external tooth 502, a sleeve SL, an internal tooth 503, an external tooth 504, a return spring 505, an annular member 506, and an actuator 507, and the state of the sun gear S2 of the second planetary gear mechanism can be rotated. 1 is an electromagnetic dog clutch mechanism that is an example of a “lock mechanism” according to the present invention that is configured to be selectively switchable between a non-locked state and a non-rotatable locked state.

  The hub 501 is an annular member that can rotate integrally with the sun gear S2. The external teeth 502 are meshing tooth-like members formed on the outer peripheral surface of the hub 501.

  The sleeve SL is an annular member configured to be movable in the illustrated stroke direction. The internal teeth 503 are meshing tooth-like members formed on the inner peripheral surface of the sleeve SL.

  The annular member 406 includes outer teeth 504 that are always meshed with the inner teeth 403 formed on the sleeve SL on the outer peripheral surface thereof. The annular member 506 is fixed to a case (not shown) that is a fixed element, and is configured so as not to rotate. Accordingly, the sleeve SL including the inner teeth 503 that mesh with the outer teeth 504 formed on the outer peripheral surface of the annular member 506 is also a non-rotatable fixing element.

  The actuator 507 is a known electromagnetic actuator capable of applying an electromagnetic force for moving the sleeve SL in the stroke direction to the sleeve SL.

  The actuator 507 includes a solenoid (electromagnet) as a driving force source, and an electromagnetic force that displaces the sleeve SL in the stroke direction is generated by supplying a driving current as an exciting current to the solenoid. It has become. The actuator 507 is electrically connected to the PCU 11 and can supply a drive current by supplying power from the PCU 11. Therefore, the operation state of the actuator 507 is also controlled by the ECU 100. When the sign of the drive current is reversed, the moving direction of the sleeve SL is reversed.

  Here, when driving force is supplied to the sleeve SL and the sleeve SL is displaced in the stroke direction to the right in the figure, the inner teeth 503 formed on the inner peripheral surface of the sleeve SL and the outer teeth formed on the outer peripheral surface of the hub 501. The teeth 502 mesh with each other. As described above, the sleeve SL cannot rotate because the inner teeth 503 always mesh with the outer teeth 504. When the inner teeth 503 and the outer teeth 502 are engaged, the hub 501 also It becomes impossible to rotate. Since the hub 501 is connected to the sun gear S2, in this state, the sun gear S2 is also locked so as not to rotate.

  On the other hand, a return spring 505 is connected to the sleeve SL. The return spring 505 is an elastic member having one end fixed to the case and the other end connected to the sleeve SL, and always urges the sleeve SL in a direction to separate it from the hub 501. Therefore, when the energization to the actuator 507 is stopped, the sleeve SL is moved to a release position where the inner teeth 503 and the outer teeth 502 are not engaged by this biasing force. When the sleeve SL moves to the release position, the hub 501 can rotate again, and the sun gear S2 returns to the unlocked state.

  The practical aspect of the “lock mechanism” of the present invention is not limited to a dog clutch mechanism such as the lock mechanism 500. For example, the lock mechanism according to the present invention may be a wet multi-plate type clutch or brake mechanism that generates an engagement force by pressing the engagement elements together by hydraulic pressure, or a so-called electromagnetic cam lock type engagement device. There may be. Moreover, although it is a dog clutch mechanism, the engagement aspect between engagement elements is not limited to the thing of this embodiment. For example, in the present embodiment, the engaging elements are each configured as an annular member, and a toothed member formed on one outer peripheral surface and a toothed member formed on the other inner peripheral surface are engaged. However, a configuration in which a tooth-like member is formed on the opposing surface of each of the engaging elements may be employed.

<Operation of Embodiment>
<Details of shift mode>
The hybrid vehicle 1 according to the present embodiment can select the fixed speed change mode and the continuously variable speed change mode as the speed change mode according to the present invention in accordance with the state of the sun gear S2 as the lock target rotation element. Here, the shift mode of the hybrid vehicle 1 will be described with reference to FIG. Here, FIG. 3 is an operation alignment chart 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. 3A, the vertical axis represents the rotation speed, and the horizontal axis represents the motor generator MG1 (uniquely sun gear S1), sun gear S2, engine 200 (uniquely carrier C1) and motor in order from the left. Generator MG2 (uniquely output rotation speed Nout) is shown.

  Here, the power split mechanism 400 is a planetary gear mechanism with two degrees of freedom constructed by four rotational elements having a differential relationship with each other, and includes a sun gear S1, a sun gear S2, a carrier C1 (ring gear R2), and When the rotational speeds of the two elements of the ring gear R1 (carrier C2) are determined, the rotational speeds of the remaining two rotational elements are inevitably determined. That is, on the operation collinear diagram, the operation state of each rotary element can be represented by one operation collinear line corresponding to one operation state of the hybrid drive device 10 on a one-to-one basis.

  In FIG. 3A, it is assumed that the operating point of the motor generator MG2 that is uniquely related to the vehicle speed V is the operating point m1. In this case, if the operating point of motor generator MG1 is operating point g1, the operating point of engine 200 connected to carrier C1, which is the remaining rotating element, is operating point e1. At this time, if the operating point of the motor generator MG1 is changed to the operating point g2 and the operating point g3 while maintaining the output rotational speed Nout as the rotational speed of the drive shaft 600, the operating point of the engine 200 is the operating point e2 and the operating point, respectively. It changes to point e3.

  That is, in this case, the engine 200 can be operated at a desired operating point by using the motor generator MG1 as the rotational speed control device. The speed change mode corresponding to this state is the continuously variable speed change mode. In the continuously variable transmission mode, the operating point of the engine 200 (the operating point in this case means one operating condition of the engine 200 defined by the combination of the engine speed and the engine torque Te) is basically the engine. The optimal fuel consumption operating point at which the fuel consumption rate of 200 is minimized is controlled.

  Here, in the continuously variable transmission mode, of course, the MG1 rotational speed Nmg1 needs to be variable. If the MG1 rotational speed Nmg1 is variable, the rotational speed of the sun gear S2 must also be variable due to the configuration of the differential mechanism with two degrees of rotation. For this reason, when the continuously variable transmission mode is selected, the driving state of the lock mechanism 500 is controlled so that the sun gear S2 is in the unlocked state. The sun gear S2 in the unlocked state only idles at a rotational speed that is uniquely determined according to the rotational state of the other three rotating elements, and does not contribute to power transmission in the continuously variable transmission mode.

  In the power split mechanism 400, in order to supply the torque Ter corresponding to the engine torque Te described above to the drive shaft 600, the rotation shaft of the sun gear S1 (here, “sun gear shaft” is referred to for convenience). It is necessary to supply from the motor generator MG1 to the sun gear shaft, a reaction force torque that is equal in magnitude to the above-described torque Tes appearing in FIG. In this case, at the operating point in the positive rotation region such as the operating point g1 or the operating point g2, MG1 is in a power regeneration state (that is, a power generation state) with a positive rotational negative torque. As described above, in the continuously variable transmission mode, the motor generator MG1 functions as a reaction force element, so that a part of the engine torque Te is supplied to the drive shaft 600 and a part of the engine torque Te distributed to the sun gear shaft. Power regeneration (power generation) is performed in the department. When the torque required for drive shaft 600 (that is, the required torque of hybrid vehicle 1) is insufficient due to the direct torque from engine 200, this regenerative power is used to drive shaft 600 from motor generator MG2. On the other hand, the assist torque Tmg2 is appropriately supplied.

  On the other hand, for example, when driving at a high speed and a light load, for example, in an operating condition where the engine rotational speed Ne is low for a high output rotational speed Nout, MG1 is an operating point in the negative rotational region such as the operating point g3. . Since motor generator MG1 outputs a negative torque as a reaction torque of engine torque Te, in this case, MG1 enters a state of negative rotation negative torque and enters a power running state. That is, in this case, torque Tmg1 from motor generator MG1 is transmitted to drive shaft 600 as the drive torque of hybrid vehicle 1.

  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 600. In this case, motor generator MG2 is in a positive rotation negative torque state and is in a power regeneration state. In such a state, an inefficient electric path called so-called power circulation, in which the driving force from MG1 is used for power regeneration in MG2 and MG1 is driven by this regenerative power, is generated. . In the state where the power circulation occurs, the system efficiency of the hybrid drive device 10 decreases.

  Therefore, in the hybrid vehicle 1, the sun gear S <b> 2 is controlled to be locked by the lock mechanism 500 in an operation region that is determined in advance as such that such power circulation can occur. This is shown in FIG. When the sun gear S2 shifts to the locked state by the lock mechanism 500, the operating point of the sun gear S2 is fixed to the illustrated operating point c1 corresponding to zero rotation speed.

  In this case, the remaining engine rotation speed Ne and MG1 rotation speed Nmg1 are uniquely fixed by the output rotation speed Nout and the zero rotation, and the operating points are illustrated as e4 and g4, respectively. That is, when the sun gear S2 is locked, the engine rotational speed Ne is uniquely determined by the vehicle speed V and the unambiguous MG2 rotational speed Nmg2 (that is, the gear ratio is constant). The shift mode corresponding to this state is the fixed shift mode. In this state, the engine rotational speed NE is lower than the output rotational speed Nout (MG2 rotational speed Nmg2 in the drawing for convenience), and a so-called overdrive state is realized. Therefore, the lock of the sun gear S2 realized by the lock mechanism 500 is referred to as “O / D lock” or the like.

  In the fixed speed change mode, the reaction torque of the engine torque Te that should be borne by the motor generator MG1 can be replaced by the physical engagement force of the lock mechanism 500. That is, in this case, it is not necessary to control motor generator MG1 in both the power regeneration state and the power running state, and motor generator MG1 can be stopped. Therefore, basically, there is no need to operate motor generator MG2, and MG1 and MG2 are in an idling state. After all, in the fixed speed change mode, the drive torque appearing on the drive shaft 600 is only the directly achieved portion (see the above formula (2)) of the engine torque Te divided by the power split mechanism 400 toward the drive shaft 600 side, and hybrid drive The device 10 only performs mechanical power transmission, and the transmission efficiency is improved.

  In the fixed speed change mode, motor generator MG2 does not necessarily have to be stopped. For example, the hybrid vehicle 1 is provided with various electric auxiliary devices, and appropriate electric power is required to drive the electric auxiliary devices. The motor generator MG2 may perform small-scale power regeneration in order to supply the battery 12 with power corresponding to the driving power. In this case, ECU 100 controls engine torque Te so that the directly achieved portion of engine torque Te is surplus with respect to the torque required to drive the vehicle, and the surplus torque is regenerated by motor generator MG2.

  Apart from that, the ECU 100 constantly performs SOC feedback control for maintaining the SOC of the battery 12 at the target value. ECU 100 controls the electric power regeneration amounts of motor generator MG1 and motor generator MG2 so that the SOC of battery 12 is maintained at a target value of, for example, about 70% to 80%, regardless of whether it is continuously variable transmission mode or fixed transmission mode. For example, when the SOC is lower than the target value, the power regeneration amount is relatively large, and when the SOC is higher than the target value, the operation of the engine 200, MG1, and MG2 is increased so that the amount of power taken out from the battery 12 increases. The state is controlled.

<Details of fail-safe control>
The lock mechanism 500 is a dog clutch mechanism that exerts an engagement force by engaging a tooth-like member between the sleeve SL and the hub 501. For example, the lock mechanism 500 is caused by an accidental change, aging, or manufacturing. For example, the tooth-like members may bite, adhere or adhere, the electromagnetic force of the actuator 507 is not turned off, or the return spring 505 does not operate smoothly. You may not be able to make it. Or, conversely, there are cases where it is impossible to shift the sun gear S2 to the locked state, for example, the tooth-like members do not mesh with each other, the electromagnetic force of the actuator 507 is not turned on, or the urging force of the return spring 505 is excessive.

  In the latter case, the speed change mode is only fixed to the continuously variable speed change mode, and there is no practical problem. However, if a malfunction on the release side occurs as in the former case, the speed change mode is fixed to the fixed speed change mode. Therefore, the above-described practical benefits of the fixed speed change mode are partially enjoyed, but problems to be solved may arise.

  For example, when the hybrid vehicle 1 stops in a state where the fixed speed change mode is selected, power supply from the MG 2 is indispensable in order to make the hybrid vehicle 1 restart (this is also preferable in the stepless speed change mode). However, in the continuously variable transmission mode, the engine 200 is cranked by supplying cranking torque from the MG1, and the engine torque Te is used after the engine 200 is started. Can also be launched).

  On the other hand, in a situation where it is impossible to select other than the fixed speed change mode, the engine 200 may be required to operate in a rotation region below the lower limit rotation speed. In such a case, it is necessary to prevent a decrease in drivability, and it is necessary to stop the engine 200 and switch the traveling mode from the HV (Hybrid Vehicle) mode to the EV (Electric Vehicle) mode. Here, since the EV mode is a mode in which the vehicle is driven only by the power of MG2 by supplying power from the battery 12, power regeneration is basically not performed except during deceleration. On the other hand, when traveling in the fixed speed change mode, as described above, the power regeneration by MG2 is basically small, and the SOC of the battery 12 after the EV traveling is correspondingly reduced extremely. There is a possibility.

  Therefore, when the lock mechanism 500 is not in a normal state in which the sun gear S2 can be shifted to the unlocked state due to a malfunction on the release side (this state is referred to as “unnormal state” as appropriate), the hybrid vehicle 1 In some cases, it may be difficult to start the car due to insufficient power required for restart. In order to solve such a problem, fail safe control is executed by the ECU 100 in the hybrid vehicle 1 according to the present embodiment.

  Here, the details of the fail-safe control will be described with reference to FIG. FIG. 4 is a flowchart of the failsafe control.

  In FIG. 4, the ECU 100 determines whether or not it is a determination timing (step S101). Here, the “determination timing” is a timing defined as a timing for determining whether or not the lock mechanism 500 is in a normal state (a state in which the sun gear S2 can be shifted to the unlocked state). Thus, in the present embodiment, this corresponds to the time when the ignition is turned on when the hybrid vehicle 1 is started and the time when a shift request is made to switch the shift mode from the fixed shift mode to the continuously variable shift mode. When it is not the determination timing (step S101: NO), the ECU 100 shifts the process to step S103.

  When it is the determination timing (step S101: YES), the ECU 100 executes a determination process (step S102).

  In the determination process performed in a state where the fixed speed change mode has already been selected, the ECU 100 controls the actuator 507 to perform normal release control for moving the sleeve SL to the release position. On the other hand, if the determination process is performed when the ignition is on, the sleeve SL in the release position is stroked toward the hub, the sun gear S2 is once locked, and then the sleeve SL is returned to the release position again. In any case, when the sleeve SL finally moves normally to the return position, it is determined that the lock mechanism 500 is in a normal state, and a non-releaseable flag that defines whether or not the lock mechanism 500 is in a normal state. Is controlled to the off state. On the other hand, if the sleeve SL does not move normally to the return position within a predetermined time, it is determined that the lock mechanism 500 is not in a normal state, and the release disable flag is controlled to be in an on state.

  Note that the determination process may have any form as long as it can be determined whether or not the lock mechanism 500 is in a normal state. For example, the actuator 507 is driven under a driving condition predetermined for the determination process. You may control.

  In step S103, it is determined whether or not the release disable flag is in an on state. When the unreleasable flag is in an off state (step S103: NO), that is, when the lock mechanism 500 is in a normal state, the ECU 100 returns the process to step S101. That is, in this case, the fail-safe control is substantially equivalent to nothing being performed, and the traveling state of the hybrid vehicle 1 is controlled by various controls separately executed by the ECU 100.

  On the other hand, when the release impossible flag is in the on state (step S103: YES), the ECU 100 turns on the MIL 15 (step S104), notifies the driver that the lock mechanism 500 is not in the normal state, and displays the regeneration map. Change (step S105). The period after step S103 branches to “YES” is an example of the “fail-safe request period” according to the present invention.

  Here, the “regeneration map” is a control map that prescribes a power regeneration practice mode in the fixed speed change mode stored in the ROM. The regeneration map is used when the lock mechanism 500 is in a normal state as a map in which the driving conditions (for example, the vehicle speed V and the required driving force Ft) of the hybrid vehicle 1 are associated with whether or not the power regeneration can be performed. Two types are stored: a reference regeneration map and a fail-safe regeneration map used when the lock mechanism 500 is not in a normal state. In step S105, the ECU 100 changes the regeneration map from the reference regeneration map to the fail-safe regeneration map.

  More specifically, in the fail-safe regeneration map, the power regeneration area that is determined to perform power regeneration is expanded as compared with the reference regeneration map.

  Therefore, when the regeneration map is switched to the fail-safe regeneration map, the frequency at which motor generator MG2 performs power regeneration using a part of engine torque Te in the fixed speed change mode increases. Therefore, the SOC of the battery 12 can be quickly returned.

  In step S105, the ECU 100 corrects the amount of power regeneration per hour to the increasing side by correcting various feedback control terms in the SOC feedback control of the battery 12 described above. In this case, the directly achieved portion of the engine torque Te is corrected to the increase side as compared with the case where the lock mechanism 500 is in a normal state, and the surplus torque used for power regeneration increases. As a result, the amount of power regeneration per hour in motor generator MG2 can be increased. Note that such an increase in the power regeneration amount gives an offset to the target power regeneration amount determined according to the deviation between the current SOC and the target SOC, for example, without correcting the feedback control term. It may be realized by multiplying the correction coefficient.

  Further, in step S105, the ECU 100 sets the target SOC related to the SOC feedback control of the battery 12 described above to a normal value (in addition to the expansion of the power regeneration region and the increase in the amount of power regeneration per time) as described above. For example, the correction is made to be higher (for example, about 90%) than 70% to 80%. As a result, the battery 12 can eventually store more power. Each operation according to step S105 is an example of the operation of the “correction unit” according to the present invention.

  In the present embodiment, as the operation of the correction means according to the present invention, the power regeneration area is expanded, the power regeneration amount per hour is corrected to the increase side, and the target SOC is corrected to the increase side. Each of these may be an example of the operation of the “correction unit” according to the present invention.

  When the regeneration map is changed, ECU 100 determines whether engine 200 is in an operating state (step S106). When the engine 200 is in an operating state (step S106: YES), the ECU 100 determines whether or not the engine speed Ne of the engine 200 is equal to or lower than a preset lower limit value Ne1 (step S107).

  Here, the lower limit value Ne1 is the lowest engine speed at which stable rotation of the engine 200 can be guaranteed, and is experimentally determined in advance as a value unique to the engine 200. That is, the engine 200 is permitted only to operate on the higher rotation side than the lower limit value Ne1. When the engine 200 operates in an extremely low rotation range below the lower limit value Ne1, for example, engine stall, misfire, increased vibration, worsened emission, etc. may be manifested, leading to a decrease in drivability. For example, the lower limit Ne1 is set to a value of about 800 rpm.

  When the engine rotational speed Ne is equal to or less than the reference value Ne1 (step S107: YES), the ECU 100 stops the engine 200 in the operating state (specifically, the engine is controlled to stop by stopping the fuel supply). This means that the travel mode under the fixed speed change mode is the conventional HV mode (in this case, the engine travels mainly using only the power of the engine 200, but power can be supplied from the MG2. In view of the above, the travel mode may be handled as the HV mode) to switch to the EV mode (step S108). That is, at this time, the hybrid vehicle 1 starts so-called EV traveling only by power supply from the motor generator MG2.

  When the travel mode is switched to the EV mode or when it is determined in step S106 that the engine 200 is not in an operating state (step S106: NO), that is, when the hybrid vehicle 1 is already performing EV travel, the ECU 100 Then, it is determined whether or not the engine rotational speed Ne is equal to or higher than the starting reference value Ne2 (Ne2> Ne1) (step S109). The starting reference value Ne2 is a value on the higher rotation side than the above-described lower limit value Ne1, and is previously experimentally, empirically, theoretically used as a value that defines whether or not the restart of the engine 200 is permitted. Alternatively, it is set based on simulation or the like. The starting reference value Ne2 may be a value of about 1000 rpm, for example.

  Here, when the starting reference value that defines whether or not to restart the engine 200 in the engine stop state is set to the above-described lower limit value Ne1, the vehicle speed V of the hybrid vehicle 1 and the engine speed Ne are the lower limit values. The engine 200 may be repeatedly started and stopped, for example, when it is in a rotation region that fluctuates near Ne1.

  As described above, when the start frequency of the engine 200 is high, for example, the power balance and drivability of the battery 12 may be deteriorated. Therefore, the starting reference value Ne2 is set on the higher rotation side than the lower limit value Ne1, and an increase in the starting frequency of the engine 200 is suppressed.

  It should be noted that such an effect relating to the suppression of the start frequency of the engine 200 is that, in addition to setting the start reference value on the higher rotation side than the lower limit value Ne1, the engine rotation speed Ne is higher than the lower limit value Ne1. This is also ensured by a technique such as permitting start-up when the rotating area has remained for a sufficient time. In this case, the reference value defining the rotation region on the high rotation side may be a value on the low rotation side with respect to the starting reference value Ne2. Further, engine 200 may be permitted to start when any one of these different starting conditions is satisfied. In any case, it is possible to suppress the start frequency of the engine 200 as compared with the case where the start and the engine stop are controlled only by the lower limit value Ne1.

  When the engine speed Ne is equal to or higher than the start reference value Ne2 (step S109: YES), the ECU 100 starts the engine 200 (step S110) and executes the travel control in the O / D locked state in which the sun gear S2 is locked. (Step S111). In step S107, if the engine speed Ne is higher than the lower limit value Ne1 (step S107: NO), that is, if the engine 200 does not need to be stopped, the ECU 100 performs processing. Is transferred to step S111.

  Here, when starting the engine 200 in step S110, physical vibration using the engine 200 as a vibration source is generated as the combustion stroke of each cylinder is started. This physical vibration is transmitted as a so-called torque shock to the drive shaft 600 in a directly connected state, particularly in the fixed speed change mode, and causes drivability to deteriorate.

  Therefore, when starting engine 200 in step S110, ECU 100 attaches vibration suppression control using motor generator MG1.

  More specifically, since the vibration mode on the time axis of the engine 200 at the time of starting, for example, the vibration waveform can be grasped experimentally in advance, a damping torque having a waveform that cancels the starting waveform in advance is applied to the motor. If supplied from the generator MG1, physical vibration using the engine 200 as a vibration source can be suppressed. Such a waveform of the damping torque is stored in advance as a map.

  On the other hand, when such vibration damping torque is supplied from motor generator MG1, a part of this vibration damping torque may be transmitted to drive shaft 600 as drive torque. Therefore, ECU 100 absorbs this excess torque by motor generator MG2 in the process of executing vibration suppression control by motor generator MG1. That is, power regeneration is executed. Thus, by controlling each motor generator cooperatively, the engine 200 can be started without giving a torque shock to the extent that the drive shaft 600 becomes manifest as a deterioration in drivability.

  The ECU 100 determines whether there is a reverse travel request for the hybrid vehicle 1 during the fail safe request period in which the lock mechanism 500 is not in a normal state and the fixed speed change mode is selected (step S112). If there is no reverse travel request (step S112: NO), the process proceeds to step S115.

  On the other hand, when there is a reverse travel request (step S112: YES), ECU 100 limits MG2 torque Tmg2 that is the output torque of motor generator MG2 (step S115), and sets vehicle speed V of hybrid vehicle 1 to, for example, 20 km / The upper limit is set to about h (step S116). Thus, by giving a certain restriction to the torque supplied to the drive shaft 600 and the vehicle speed V, it is possible to protect the engine 200 that is forced to reversely rotate. The torque limit is experimentally determined in advance as a value that can be received by the engine 200 in the reverse rotation state with a sufficient margin.

  When the vehicle speed is limited or when there is no reverse travel request (step S112: NO), the ECU 100 determines whether or not the lock mechanism 500 has returned to the normal state (step S115). Supplementally, after the execution of the determination process in step S102, the ECU 100 maintains and fixes the drive condition of the lock mechanism 500 at the drive condition for setting the sun gear S2 to the unlocked state. Accordingly, when the lock mechanism 500 temporarily or accidentally falls into an abnormal state due to some cause, the lock mechanism 500 may return to the normal state by accidentally eliminating the cause. It can be enough. Therefore, the ECU 100 is configured to periodically refer to the rotational speed of the sun gear S2 and constantly grasp the latest state of the lock mechanism 500. If the lock mechanism 500 is not in a normal state (step S115: NO), that is, if the sun gear S2 continues to be locked, the ECU 100 shifts the process to step S101.

  On the other hand, when the lock mechanism 500 returns to the normal state (step S115: YES), that is, when the shift mode is switched from the fixed shift mode to the continuously variable shift mode, the ECU 100 controls the disengagement determination flag to the off state. Then, shock reduction processing is executed (step S116). Here, the shock reduction process means a process for smoothly and shocklessly switching the transmission mode from the fixed transmission mode to the continuously variable transmission mode.

  This shock reduction process may be slightly different depending on whether the hybrid vehicle 1 is in the EV mode or the HV mode when step S115 branches to the “YES” side. That is, when hybrid vehicle 1 is performing EV traveling in the EV mode, ECU 100 starts motor generator MG1 that applies reaction torque to engine 200, and then starts engine 200. At this time, the motor generator MG2 and the motor generator MG1 are cooperatively controlled so that the drive torque appearing on the drive shaft 600 does not become discontinuous in the transition period when the reaction force element switches from the sun gear S2 to MG1. When the hybrid vehicle 1 is traveling mainly in the HV mode with only the engine direct torque, the starting process of the engine 200 is unnecessary, and the ECU 100 prevents the torque shock caused by the switching of the reaction force element from becoming obvious. The motor generator MG1 and the motor generator MG2 are cooperatively controlled.

  When the torque shock during the transitional transition period of the reaction force element is alleviated in this way, the ECU 100 controls the switching prohibition flag to be in an on state (step S117). Here, the switching prohibition flag is a flag that regulates whether or not switching of the transmission mode from the continuously variable transmission mode to the fixed transmission mode should be prohibited, and is controlled to be in an on state when the switching is prohibited. It has a configuration.

  That is, in fail-safe control, once the lock mechanism 500 is in an abnormal state, the shift mode to the fixed shift mode is not forced so that the inconvenient traveling control in the fixed shift mode is not forced again. Switching is prohibited. In this case, the MIL 15 remains controlled to be lit, and the driver is encouraged to take an early action. When the switching prohibition flag is controlled to be in the on state, ECU 100 returns the process to step S101 and repeats a series of processes.

  When the switching prohibition flag is controlled to be in the ON state, it is determined that the determination timing is not unconditionally in the determination process in step S101. For this reason, when there is a history that the lock mechanism 500 has fallen into an abnormal state, the determination process is not executed when the ignition is next turned on. Further, after the lock mechanism 500 returns to the normal state, switching to the fixed transmission mode is prohibited, so that switching of the transmission mode from the fixed transmission mode to the continuously variable transmission mode does not occur. In other words, when the lock mechanism 500 returns from the abnormal state to the normal state and only the continuously variable transmission mode is permitted as the transmission mode, the fail-safe control only loops between step S101 and step S103. To finish its role.

  As described above, according to the fail-safe control according to the present embodiment, the lock mechanism 500 is not in a normal state in which the sun gear S2 can be shifted from the locked state to the non-locked state, and is fixed as a shift mode. In the fail safe request period in which the mode is selected, the power regeneration amount in motor generator MG2 is corrected to the increase side.

  For this reason, even if the hybrid vehicle 1 is in the EV traveling state for a long period of time due to, for example, restrictions on the engine 200 side under the fixed speed change mode, the electric power necessary to start the hybrid vehicle 1 at the next start is obtained. The battery 12 can be sufficiently secured. For this reason, the hybrid vehicle 1 can be started reliably at the next start. Thus, by ensuring the certainty of re-starting, the freedom degree and safety of evacuation travel improve more, and suitable fail safe is implement | achieved.

  In the fail-safe control according to the present embodiment, if it is determined in the determination process according to step S102 that the lock mechanism 500 is not in a normal state, the shift mode has already shifted to the fixed shift mode. Yes. Therefore, the “fail safe request period in which it is determined that the lock mechanism is not in a normal state and the fixed shift mode is selected as the shift mode” according to the present invention is a period in which the lock mechanism 500 is determined not to be in a normal state. That is, it is equivalent to the period during which the release impossible flag is controlled to be in the on state. However, in practical operation, it is possible to determine whether or not the lock mechanism 500 is in a normal state without shifting the sun gear S2 to the lock state (for example, the actuator 507 is clearly out of order). In such a case, if switching to the fixed transmission mode is prohibited when such a determination is made, the regeneration map is intentionally changed from the reference regeneration map to the failsafe regeneration map. There is no need to switch.

  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 can be applied to a hybrid vehicle capable of switching the transmission mode between the continuously variable transmission mode and the fixed transmission mode.

  DESCRIPTION OF SYMBOLS 1 ... Hybrid vehicle, 10 ... Hybrid drive device, 100 ... ECU, 200 ... Engine, 300 ... Input shaft, 400 ... Power split mechanism, MG1 ... Motor generator, MG2 ... Motor generator, 500 ... Lock mechanism, 600 ... Drive shaft, 700: MG2 speed change mechanism.

Claims (9)

An internal combustion engine;
A power transmission mechanism comprising a plurality of rotational elements capable of differentially rotating with each other, including a first rotational element, a second rotational element coupled to a drive shaft connected to an axle, and a third rotational element coupled to the internal combustion engine; ,
A first motor generator coupled to the first rotating element and capable of adjusting a rotational speed of the internal combustion engine;
A second motor generator configured to be able to input and output power to and from the drive shaft;
Power storage means that functions as a power source for the first and second motor generators and can be charged by power regeneration in the first and second motor generators;
The state of the one rotating element provided in the power transmission mechanism can be selectively switched between a non-rotatable locked state and a rotatable non-locked state, and (1) the one rotating element is A continuously variable transmission mode in which the speed ratio, which is the ratio between the rotational speed of the internal combustion engine and the rotational speed of the drive shaft, is continuously variable by setting the unlocked state; and (2) the one rotational element A device that controls a hybrid vehicle including a lock mechanism that can select a fixed transmission mode in which the transmission gear ratio is fixed by setting the transmission ratio in a locked state.
Determining means for determining whether or not the lock mechanism is in a normal state in which the shift mode can be switched from the fixed shift mode to the continuously variable shift mode;
In a fail-safe request period in which it is determined that the lock mechanism is not in the normal state and the fixed shift mode is selected as the shift mode, the power regeneration amount of the second motor generator is set to the normal state. A control device for a hybrid vehicle, comprising: correction means for correcting the increase in comparison with a certain case. Further comprising first control means for controlling the power regeneration amount based on a predetermined regeneration condition;
The correction means corrects at least one of (1) a target charge amount of the power storage means, (2) the power regeneration amount per time, and (3) a power regeneration frequency of the second motor generator,
The control device for a hybrid vehicle according to claim 1, wherein the first control means controls the power regeneration amount based on at least one of the corrections as the regeneration condition. The control device for a hybrid vehicle according to claim 1, further comprising notification means for notifying a driver that the lock mechanism is not in the normal state. The hybrid vehicle can select an EV traveling mode in which the required driving force of the hybrid vehicle is covered by a power supply from the second electric motor to the drive shaft as a traveling mode,
The hybrid vehicle control device comprises:
Stop means for stopping the engine operation of the internal combustion engine when the rotational speed of the internal combustion engine is equal to or lower than a lower limit value in the fail safe request period;
4. The apparatus according to claim 1, further comprising: a second control unit configured to control the second motor generator so that the traveling mode is switched to the EV traveling mode when the engine operation is stopped. The hybrid vehicle control device according to claim 1. When the rotational speed of the internal combustion engine reaches a reference value greater than the lower limit value after the engine operation stops or the rotational speed of the internal combustion engine continues and stays in a rotational speed range greater than the lower limit value, The hybrid vehicle control device according to claim 4, further comprising start means for restarting the internal combustion engine. The apparatus further comprises third control means for controlling the first motor generator so that vibrations generated when the internal combustion engine is restarted are suppressed when the internal combustion engine is restarted. The hybrid vehicle control device according to claim 5. The determining means determines whether or not the lock mechanism is in the normal state at a predetermined cycle,
The hybrid vehicle control device comprises:
And switching means for switching the shift mode to the continuously variable transmission mode when it is determined that the lock mechanism has returned to the normal state when the EV travel mode is selected as the travel mode. The control device for a hybrid vehicle according to any one of claims 4 to 6, wherein the control device is a hybrid vehicle control device. 2. The apparatus according to claim 1, further comprising prohibition means for prohibiting switching of the shift mode from the continuously variable transmission mode to the fixed transmission mode when it is determined that the lock mechanism is not in the normal state. The hybrid vehicle control device according to claim 7. 9. The apparatus according to claim 1, further comprising a limiting unit configured to limit a vehicle speed of the hybrid vehicle to a predetermined value or less when the hybrid vehicle is requested to travel backward during the fail-safe request period. The hybrid vehicle control device according to one item.

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