JP2012254739A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of hybrid vehicle which can appropriately switch a traveling state from an electric vehicle state to a hybrid vehicle state even if in a situation where a big driving force is required during uphill traveling.SOLUTION: The control device of hybrid vehicle which includes a clutch mechanism which can successively change a transmission torque capacity between an internal combustion engine and a driving wheel and can switch an EV state and an HV state which makes the internal combustion engine operate, is provided with an internal-combustion engine starting means (steps S4 and S5) that starts the internal combustion engine in the state where the rotation speed of a crankshaft is raised while maintaining the rotation speed of the drive shaft by collaborative control of output of a first electric motor and an engagement and release operation of the clutch mechanism, when switching the traveling state of the hybrid vehicle during uphill traveling from the electric vehicle state to the hybrid vehicle state.

Description

  The present invention relates to a control apparatus for a hybrid vehicle including an internal combustion engine and an electric motor as a driving force source, and more particularly, an electric vehicle state in which only the electric motor is operated to generate a driving force, and the vehicle is driven by operating the internal combustion engine. The present invention relates to a control device for a hybrid vehicle capable of switching and driving a hybrid vehicle state.

  A hybrid vehicle is a vehicle in which an internal combustion engine such as a gasoline engine or a diesel engine and an electric motor such as a motor / generator are mounted as a plurality of driving force sources, and the fuel consumption is improved while utilizing the characteristics of the internal combustion engine and the electric motor. It is possible to improve and reduce exhaust gas. For example, in a hybrid vehicle, the internal combustion engine can be operated at an operating point with good combustion efficiency, and the drive torque required for the vehicle can be applied by an electric motor. Furthermore, it is possible to regenerate energy during deceleration and use the electric power generated at that time for traveling. Therefore, the hybrid vehicle can improve fuel efficiency while satisfying the demand for traveling. An example of an invention relating to such a hybrid vehicle is described in Patent Document 1.

  In the invention described in Patent Document 1, a power adjustment device capable of adjusting the magnitude of power transmitted between a plurality of rotating shafts by exchanging electric power, and an electric motor are provided between an engine output shaft and a drive shaft. A hybrid vehicle arranged in series between the coupling mechanism for coupling and decoupling the power adjustment device and the electric motor, and the power adjustment device and the electric motor by holding one of the rotation shafts of the power adjustment device. It has a configuration provided with a holding mechanism that enables conversion between electric power and power in the power adjustment device when disconnected. In Patent Document 1, it is detected whether or not motoring of the engine is to be performed. When it is detected that the engine is in an operating state in which motoring is to be performed, The point to detach is described.

  Patent Document 2 discloses an engine for driving a vehicle, a clutch for substantially opening a power transmission path between the wheels and the engine, and a motor connected to the wheels for driving the vehicle. In a region where the engine cannot be started by engaging the clutch, the clutch is released, the engine is started by the starter motor, and the engine is started by engaging the clutch. Where possible, an invention is described that is configured to start the engine by engaging its clutch. Specifically, in Patent Document 2, if there is an engine start request during a motor travel mode in which the engine is stopped and the motor travels, it is determined whether or not the vehicle speed has reached a pushable vehicle speed. When the vehicle speed is greater than or equal to the pushable vehicle speed, the clutch is engaged and the engine is started, that is, when the engine is started by so-called push and the vehicle speed is less than the pushable vehicle speed, It describes that the engine is started by cranking the engine with a starter motor with the clutch released.

JP 2000-209706 A JP 2001-107763 A

  Applying the configuration of the coupling mechanism in the invention described in the above-mentioned Patent Document 1 and the configuration of the clutch in the invention described in Patent Document 2, it is considered to smoothly switch the running state of the hybrid vehicle. It is done. That is, the above-described coupling mechanism or clutch is constituted by a friction clutch capable of continuously changing the transmission torque capacity by slip engagement, for example, and the friction clutch is engaged while sliding. By gradually increasing the transmission torque between the internal combustion engine and the drive wheels, the internal combustion engine can be smoothly cranked and started by the power from the drive wheels. Therefore, when traveling in an electric vehicle state in which only the electric motor is operated, the internal combustion engine stopped during that time is started quickly and smoothly, and the traveling state is switched to a hybrid vehicle state in which the internal combustion engine is also operated together with the electric motor. be able to.

  Such switching of the traveling state of the hybrid vehicle requires a greater driving force when the hybrid vehicle is traveling in an electric vehicle state, for example, when approaching an uphill road or when suddenly accelerating. Therefore, there is a case where switching from the electric vehicle state to the hybrid vehicle state in which the driving force can be generated by the output of the internal combustion engine is required. In such a case, if the clutch is engaged while being slid to start the internal combustion engine, that is, if the clutch is slip-engaged and the internal combustion engine is cranked, the clutch is passed through the clutch. In some cases, the drive torque transmitted to the drive wheels is reduced.

  For example, when the driving state is switched from the electric vehicle state to the hybrid vehicle state in response to a request for increasing the driving force during uphill driving, if the driving torque is reduced by slipping the clutch as described above, Driving force may be insufficient. Further, when the driving state is switched from the electric vehicle state to the hybrid vehicle state in response to the driver's acceleration request and the driving torque is reduced by slipping the clutch as described above, the driving intended by the driver is performed. The driving force that is actually output with respect to the force is insufficient, which may give the driver a sense of incongruity and feeling of tackiness. As a result, the drivability of the hybrid vehicle may be reduced.

  In this way, even when a large driving force is required, for example, when traveling on an uphill or suddenly accelerating, the electric vehicle state and the hybrid vehicle can be achieved without incurring a driving force deficiency or drivability on an uphill road. There is still room for improvement in order to appropriately switch the driving state between the two states and drive the hybrid vehicle.

  The present invention has been made by paying attention to the above technical problem.For example, even in a situation where a larger driving force is required than before, such as during climbing or sudden acceleration, only the electric motor is operated. It is an object of the present invention to provide a control device for a hybrid vehicle that can appropriately switch a traveling state from an electric vehicle state that travels to a hybrid vehicle state that travels by operating an internal combustion engine.

  In order to achieve the above object, the invention of claim 1 includes an internal combustion engine, a first electric motor capable of increasing / decreasing the rotational speed of the crankshaft of the internal combustion engine by controlling output, By controlling the release operation, the torque transmission path between the crankshaft and the drive shaft connected to the drive wheel so as to be able to transmit power is connected and disconnected, and the transmission torque capacity at the time of connection and disconnection is continuously reduced. A clutch mechanism that can be changed, and a second electric motor that can transmit power directly to the drive shaft, and only the second electric motor is operated or only the first electric motor and the second electric motor The hybrid vehicle is capable of selectively switching between an electric vehicle state that generates a driving force for running by operating the hybrid vehicle state that runs by operating the internal combustion engine. In the vehicle control device, when the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state when traveling on an uphill road or when an increase in driving force is requested, the relationship between the output of the first motor and the clutch mechanism An internal combustion engine starting means for starting the internal combustion engine in a state in which the rotational speed of the crankshaft is increased while maintaining or decreasing the rotational speed of the drive shaft by cooperatively controlling the combination / release operation; It is the control device characterized by comprising.

  According to a second aspect of the present invention, in the first aspect of the invention, the internal combustion engine starter can start the crankshaft in advance as a lower limit value of the rotational speed at which the internal combustion engine can autonomously rotate. The control device includes means for starting the internal combustion engine in a state where the rotational speed is increased to a value higher than the rotational speed.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the internal combustion engine and the first electric motor divide the power of the internal combustion engine into the first electric motor and the drive wheels. And the clutch mechanism is provided between the power split mechanism and the drive shaft in the torque transmission path. It is.

  According to the first aspect of the present invention, when the hybrid vehicle is traveling on an uphill road, when the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state, that is, to switch the traveling state to the hybrid vehicle state. When starting the internal combustion engine, the output of the first motor and the engagement / release operation of the clutch mechanism are controlled in a coordinated manner so that the rotational speed of the crankshaft increases while maintaining the rotational speed of the drive shaft. . Then, the internal combustion engine is started in a state where the rotational speed of the crankshaft is increased while the rotational speed of the drive shaft is maintained. When the clutch mechanism is engaged while the hybrid vehicle is running, the torque of the drive shaft decreases due to the friction torque of the internal combustion engine, etc., but the output of the first motor and the engagement / release operation of the clutch mechanism are coordinately controlled. As a result, the rotational speed of the crankshaft can be increased, and the clutch mechanism can be engaged while maintaining the rotational speed of the drive shaft. That is, it is possible to increase the number of rotations of the crankshaft without lowering the torque of the drive shaft and to engage the clutch mechanism. Therefore, even when a large driving force is required when traveling uphill or when an increase in driving force is required, the hybrid vehicle avoids a decrease in the torque of the driving shaft and does not cause a shortage of driving force on the uphill road. Can be appropriately switched from the electric vehicle state to the hybrid vehicle state.

  According to the second aspect of the present invention, when the internal combustion engine is started, the rotational speed of the output shaft of the internal combustion engine is increased to a startable rotational speed or higher at which the internal combustion engine can autonomously rotate. Thereafter, the internal combustion engine is started, for example, by igniting the internal combustion engine or injecting fuel. Therefore, when the internal combustion engine is started in order to switch the traveling state of the hybrid vehicle from the electric vehicle state to the hybrid vehicle state, the internal combustion engine can be reliably started by the internal combustion engine starting means in the present invention.

  According to the invention of claim 3, the power split mechanism for distributing the power output from the internal combustion engine to the first electric motor and the drive wheels is provided, and the clutch mechanism is set between the power split mechanism and the drive wheels. The hybrid vehicle being operated can be controlled. Therefore, when the traveling state of the hybrid vehicle configured as described above is switched from the electric vehicle state to the hybrid vehicle state, the traveling state of the hybrid vehicle is reduced without causing a decrease in drivability and insufficient driving force for climbing. It can be switched appropriately.

1 is a schematic diagram illustrating an example of a configuration and a control system of a hybrid vehicle to be controlled in the present invention. FIG. 2 is a collinear diagram for explaining a behavior during traveling in an electric vehicle state in the hybrid vehicle having the configuration shown in FIG. 1. FIG. 2 is a collinear diagram for explaining a behavior during traveling in an electric vehicle state in the hybrid vehicle having the configuration shown in FIG. 1. FIG. 2 is a collinear diagram for explaining a behavior at the time of traveling in a hybrid vehicle state (series hybrid system) in the hybrid vehicle having the configuration shown in FIG. 1. FIG. 2 is a collinear diagram for explaining a behavior at the time of traveling in a hybrid vehicle state (parallel hybrid system) in the hybrid vehicle having the configuration shown in FIG. 1. It is a flowchart for demonstrating an example of the control performed by the control apparatus of this invention. It is a figure for demonstrating the behavior at the time of performing control shown in the flowchart of FIG. 6, Comprising: It is a collinear diagram for demonstrating the behavior at the time of performing switching control of driving state. It is a figure for demonstrating the behavior at the time of performing control shown in the flowchart of FIG. 6, Comprising: It is a collinear diagram for demonstrating the behavior at the time of performing switching control of driving state. It is a figure for demonstrating the behavior at the time of performing control shown in the flowchart of FIG. 6, Comprising: It is a collinear diagram for demonstrating the behavior at the time of performing switching control of driving state. FIG. 7 is a diagram for explaining the behavior when the running state switching control shown in the flowchart of FIG. 6 is executed, and is a collinear diagram for explaining torque in each rotating element. It is a flowchart for demonstrating the other example of the control performed by the control apparatus of this invention.

  Next, the present invention will be specifically described with reference to the drawings. FIG. 1 schematically shows the configuration and control system of a hybrid vehicle to be controlled in the present invention. That is, the hybrid vehicle Ve shown in FIG. 1 includes an internal combustion engine 1 and two electric motors, ie, a first electric motor 2 and a second electric motor 3, as a driving force source. The motor 2 and the drive wheels 4 are configured to be divided.

  The internal combustion engine 1 is a power generation device that outputs power by burning fuel such as a gasoline engine, a diesel engine, or a natural gas engine. In the example shown in FIG. Equipped with an electronically controlled throttle valve or electronically controlled fuel injection device, etc. that can be controlled in an optimal manner, and optimal operation with the best fuel efficiency by electrically controlling the rotational speed for a given load A gasoline engine that can be set to a point is installed. In the following description, the internal combustion engine 1 is referred to as an engine (ENG) 1.

  Each of the first electric motor 2 and the second electric motor 3 is an electric motor having a function of either one or both of a motor and a generator. In the example shown in FIG. 1, the function as a motor and the function as a generator. A motor / generator with both functions is installed. Hereinafter, in the description of this embodiment, the electric motors 2 and 3 are referred to as a first motor / generator (MG1) 2 and a second motor / generator (MG2) 3.

  In a torque transmission path between the engine 1 and the drive wheels 4, a power split mechanism 5 for splitting the power output from the engine 1 into the first motor / generator 2 and the drive wheels 4 is provided. The power split mechanism 5 is mainly composed of a planetary gear device having a differential action. In the example shown in FIG. 1, a pinion gear disposed between a sun gear 5s and a ring gear 5r is rotated and revolved by a carrier 5c. A single pinion type planetary gear mechanism that is held in such a manner as to be possible is employed. The crankshaft 1a of the engine 1 is connected to the carrier 5c of the power split mechanism 5, the output shaft 2a of the first motor / generator 2 is connected to the sun gear 5s, and a clutch mechanism 6 and a drive described later are connected to the ring gear 5r. Via the shaft 7 and the differential 8, the drive wheel 4 is connected so that power can be transmitted. As described above, the planetary gear device of the power split mechanism 5 performs a differential action, so that the rotational speed of the crankshaft 1a of the engine 1 changes according to the rotational speed of the first motor / generator 2. Therefore, by controlling the output of the first motor / generator 2, the rotational speed of the crankshaft 1a can be controlled.

  The clutch mechanism 6 is an engagement device for connecting / disconnecting a torque transmission path between the engine 1 and the drive wheel 4, that is, between the crankshaft 1 a and the drive shaft 7, and is a ring gear of the power split mechanism 5. It is provided between 5r and the drive shaft 7. As the clutch mechanism 6, for example, a frictional engagement device that can be controlled by setting a half-engaged or slip-engaged state in addition to an engaged state and a released state, or a synchronous coupling using a synchronization mechanism or the like. A device or the like can be used. FIG. 1 shows an example in which a friction clutch capable of controlling the slip engagement state is provided. Therefore, the clutch mechanism 6 connects / disconnects the torque transmission path between the crankshaft 1a and the drive shaft 7, and continuously changes the transmission torque capacity when connecting / disconnecting the torque transmission path. Is possible.

  The drive shaft 7 includes a driven gear 7b that meshes with the drive gear 7a connected to the ring gear 5r via the clutch mechanism 6 as described above, a counter gear 7c that meshes with the ring gear 8a of the differential 8 described later, and a second motor described later. A driven gear 7d that meshes with a drive gear 9 provided on the output shaft 3a of the generator 3 is fixed so as to rotate together.

  As described above, the differential 8 has the ring gear 8 a meshed with the counter gear 7 c provided on the drive shaft 7, and the drive wheel 4 is connected to the drive shaft 10. Therefore, the engine 1 and the first motor / generator 2 are connected to the drive wheels 4 through the power split mechanism 5, the drive shaft 7, the differential 8, and the drive shaft 10 so as to be able to transmit power to each other.

  As described above, the first motor / generator 2 is configured to transmit power by interposing the power split mechanism 5, the clutch mechanism 6 and the drive shaft 7 with the drive wheel 4. The second motor / generator 3 is configured to be able to directly transmit power to and from the drive wheels 4 via the drive shaft 7. That is, the second motor / generator 3 is attached to the output shaft 3a as described above with the drive gear 9 that rotates integrally with the output shaft 3a, and the drive gear 9 meshes with the driven gear 7d of the drive shaft 7. ing. Therefore, the second motor / generator 3 is connected to the drive wheels 4 through the drive gear 9, the drive shaft 7, the differential 8, and the drive shaft 10 so as to be able to transmit power to each other. The gear pair of the drive gear 9 and the driven gear 7d is a reduction mechanism (reduction gear) for the second motor / generator 3. Therefore, the output torque of the second motor / generator 3 can be amplified and transmitted to the drive wheels 4, and a large driving force can be generated.

  As described above, each of the first motor / generator 2 and the second motor / generator 3 is configured as a well-known synchronous motor that functions not only as an electric motor but also as a generator. The first motor / generator 2 and the second motor / generator 3 are connected to a power storage device (not shown) such as a battery or a capacitor via an inverter (not shown). That is, the rotation speed or output torque when the first motor / generator 2 and the second motor / generator 3 function as motors, and the case where the first motor / generator 2 and the second motor / generator 3 function as generators. The power generation amount or the regenerative braking torque is controlled by an inverter.

  Further, the first motor / generator 2 and the second motor / generator 3 are configured to be able to exchange electric power between the motor generators 2 and 3 via an inverter. In other words, the electric power generated by either the first motor / generator 2 or the second motor / generator 3 can be consumed by the other motor / generator. For example, when the first motor / generator 2 is driven by the output of the engine 1 to function as a generator, the electric power generated by the first motor / generator 2 is supplied to the second motor / generator 3, The two-motor generator 3 can function as an electric motor. Accordingly, part of the power output from the engine 1 is once converted into electric power by the first motor / generator 2, then converted again into power by the second motor / generator 3, and the power is transmitted to the drive wheels 4. It is configured to be able to.

  An electronic control unit (ECU) 11 for controlling the operating state of the engine 1 and the motor / generators 2 and 3 is provided. The electronic control unit 11 includes, for example, a vehicle speed sensor 12 that detects the vehicle speed of the vehicle Ve, an acceleration sensor 13 that detects the longitudinal acceleration of the vehicle Ve, and an engine speed sensor 14 that detects the rotational speed of the crankshaft 1a of the engine 1. , A resolver 15 for detecting the rotation speed of the rotation shaft 2a of the first motor / generator 2 and the rotation speed of the rotation shaft 3a of the second motor / generator 3, a charge sensor 16 for detecting the charge state of the power storage device, an accelerator Detection signals are input from various sensor devices such as an accelerator opening sensor 17 that detects a driver's accelerator operation by a pedal, an accelerator lever, and the like, and an inclination angle sensor 18 that detects an inclination angle in the traveling direction of the vehicle Ve. . On the other hand, the electronic control device 11 controls a signal for controlling the engine 1 and the motor generators 2 and 3 (that is, controls an inverter and a power storage device connected to the motor generators 2 and 3). A signal or the like is output.

  In the vehicle Ve to be controlled in the present invention configured as described above, as described above, only the first motor / generator 2 or only the second motor / generator 3 is operated, or the first motor / generator is operated. An electric vehicle (EV) state in which only the second and second motor / generators 3 are operated (that is, the engine 1 is not operated) to generate a drive torque for running the vehicle Ve, and a state in which the engine 1 is operated Thus, it is possible to selectively switch between the hybrid vehicle (HV) state in which the vehicle Ve travels.

  For example, as shown in FIG. 2, the vehicle Ve can be run in the EV state by operating only the second motor / generator 3 to generate drive torque. By engaging the clutch mechanism 6 in this state, as shown in FIG. 3, the rotational speed of the ring gear 5r can be increased in the forward rotation direction (the rotation direction of the engine 1). Since the engine 1 is not started in this state, the carrier 5c connected to the engine 1 serves as a reaction force element, and the rotation speed of the first motor / generator 2 connected to the sun gear 5s is set in the reverse direction (the engine 1 Ascending in the direction opposite to the rotation direction). At this time, the first motor / generator 2 is regeneratively controlled so as to function as a generator, so that the first motor / generator 2 generates electric power while the vehicle Ve is traveling by the output of the second motor / generator 3, thereby generating a battery. Can be charged. Alternatively, the second motor / generator 3 and the first motor / generator are operated by operating the first motor / generator 2 as the motor together with the second motor / generator 3 with the clutch mechanism 6 engaged as described above. The vehicle Ve can be caused to travel by generating a larger driving force by the outputs of the two motors No. 2.

  Further, as shown in FIGS. 4 and 5, the vehicle Ve can be driven in the HV state in which the engine 1 is operated. That is, as shown in FIG. 4, the engine 1 is operated, and the electric power generated by driving the first motor / generator 2 as a generator by the output, or generated by the first motor / generator 2 and temporarily stored in the battery. The generated electric power can be supplied to the second motor / generator 3. By operating the second motor / generator 3 as a motor by the electric power to generate driving force, the vehicle Ve can be driven in a so-called series hybrid HV state.

  Then, as shown in FIG. 5, the engine 1 is operated with the clutch mechanism 6 engaged, and the reaction torque is generated by the first motor / generator 2, that is, the first motor / generator 2 By generating the output torque in the reverse direction, the output torque of the engine 1 is transmitted to the drive wheels 4 via the ring gear 5r, and a larger driving force is generated by the outputs of the second motor / generator 3 and the engine 1, thereby generating a vehicle. Ve can be run. That is, the vehicle Ve can be driven in the so-called parallel hybrid type HV state.

  Thus, the hybrid vehicle Ve in the present invention can travel by switching the traveling state between the EV state and the HV state. When switching the traveling state from the EV state to the HV state, particularly when switching the traveling state from the EV state to the HV state of the parallel hybrid system based on, for example, an increase in driving force during acceleration traveling or traveling on an uphill road. It is necessary to start the stopped engine 1 and engage the released clutch mechanism 6 to connect the torque transmission path between the crankshaft 1a and the drive shaft 7. When the clutch mechanism 6 is engaged in a state where the engine 1 is not outputting torque, as described above, the driving torque transmitted to the driving wheels 4 is reduced, and as a result, the driving force for traveling is insufficient. There is a possibility that.

  Therefore, in the control device for the hybrid vehicle Ve according to the present invention, the traveling state can be appropriately switched from the EV state to the HV state without falling short of the driving force even during acceleration traveling or climbing traveling, for example. As described above, the following control is executed. An example of the control is shown in the flowchart of FIG. The routine shown in this flowchart is repeatedly executed every predetermined short time. In FIG. 6, first, it is determined whether or not there is a switching request for the traveling state of the vehicle Ve (step S1). That is, it is determined whether or not there is a request for starting the engine 1 and switching the traveling state to the HV state for the vehicle Ve traveling in the EV state.

  The request for switching the running state from the EV state to the HV state is, for example, when the charge amount of the battery falls below a preset reference value or when a large driving force that also requires the output of the engine 1 is requested. In addition, it can be determined that there is a request for switching the running state from the EV state to the HV state. Therefore, the determination of the presence / absence of this switching request can be made based on the detection values of the charge sensor 16 and the accelerator opening sensor 17, for example.

  If there is no request for switching the running state from the EV state to the HV state, and if a negative determination is made in step S1, this routine is temporarily terminated without executing the subsequent control. On the other hand, when there is a request for switching the running state from the EV state to the HV state, if the determination in step S1 is affirmative, the process proceeds to step S2, and the driving force is increased in the uphill running state. It is determined whether or not there is. For example, when the vehicle Ve is traveling on an uphill road having a predetermined angle or more and the driving force is increased for the uphill driving, it is determined that the driving force is increased during the uphill driving. Can do. Therefore, the determination of this state can be made based on the detection values of the inclination angle sensor 18 and the accelerator opening sensor 17 and the like. The inclination angle of the uphill road can be determined based on, for example, the detection values of the vehicle speed sensor 12 and the acceleration sensor 13 in addition to the detection value of the inclination angle sensor 18.

  This step is based on the fact that the state of the vehicle Ve is not a state in which the driving force is increased at the time of traveling uphill, for example, that the road being traveled is not an uphill road, or is not an uphill road that requires an increase in driving power. When a negative determination is made in S2, the process proceeds to step S3, and the traveling state of the vehicle Ve is switched from the EV state to the HV state while maintaining the rotation speed of the first motor / generator 2 at “0”. This is because the transmission torque capacity of the clutch mechanism 6 is gradually increased to connect the torque transmission path between the crankshaft 1 a and the drive shaft 7, so that the rotational speed of the crankshaft 1 a is started to start the engine 1. Is raised, that is, the engine 1 is cranked.

  Specifically, as shown in FIG. 7, the clutch mechanism 6 released in the EV state is slip-engaged. And the transmission torque capacity of the clutch mechanism 6 is gradually increased by gradually increasing the degree of engagement in the slip engagement state. Then, as the transmission torque capacity increases, the rotation speed of the ring gear 5r increases in the forward rotation direction. At this time, the first motor / generator 2 is controlled so as to generate torque in the reverse rotation direction and maintain the rotational speed at “0”. As a result, the rotational speed of the crankshaft 1a of the engine 1 connected to the carrier 5c increases in the forward direction. Therefore, the engine 1 is cranked by controlling the slip engagement state of the clutch mechanism 6 gradually toward the complete engagement state, that is, controlling the transmission torque capacity of the clutch mechanism 6 to gradually increase. Thus, the rotational speed of the crankshaft 1a can be increased to a startable rotational speed Nes that is a lower limit value of the rotational speed at which the engine 1 can autonomously rotate.

  On the other hand, if the state of the vehicle Ve is a state in which the driving force is increased when traveling on an uphill road, if the determination in step S2 is affirmative, the process proceeds to step S4, and the rotational speed of the first motor / generator 2 increases. Thus, the traveling state of the vehicle Ve is switched from the EV state to the HV state. This is the traveling state switching control by the “internal combustion engine starting means” in the present invention, and by controlling the output of the first motor / generator 2 and the engagement / release operation of the clutch mechanism 6 in cooperation with each other, This is a control for starting the engine 1 in a state where the rotational speed of the crankshaft 1a is increased while maintaining the rotational speed of the drive shaft 7.

  Specifically, as shown in FIG. 8, first, the first motor / generator 2 is subjected to power running control so that the rotation speed of the output shaft 2 a, that is, the sun gear 5 s increases in the forward rotation direction. By increasing the rotation speed of the first motor / generator 2 in the forward rotation direction, the rotation speed of the crankshaft 1a connected to the carrier 5c can be increased in the forward rotation direction. When the clutch mechanism 6 is engaged for transmission to the drive shaft 7, the torque on the drive shaft 7 side may decrease. Therefore, in the “internal combustion engine starting means” in the present invention, the control for increasing the rotation speed of the crankshaft 1a by the first motor / generator 2 and the control for engaging the clutch mechanism 6 are coordinated. Executed.

  That is, as shown in FIG. 9, the rotation speed of the crankshaft 1a is increased by the output of the first motor / generator 2, and the clutch mechanism 6 is gradually engaged to connect the torque transmission path. That is, the clutch mechanism 6 is slip-engaged and the transmission torque between the crankshaft 1a and the drive shaft 7 is gradually increased. At this time, the rotation speed of the carrier 5c, that is, the rotation speed of the crankshaft 1a is set so as to be equal to or exceeds the startable rotation speed Nes, and the rotation speed of the ring gear 5r, that is, the crank of the clutch mechanism 6 The rotational speed of the first motor / generator 2 so that the rotational speed of the engaging member 6a on the shaft 1a side becomes the rotational speed of the driving shaft 7, that is, the rotational speed of the engaging member 6b on the driving shaft 7 side of the clutch mechanism 6. And the engagement operation of the clutch mechanism 6 are controlled in a coordinated manner. In other words, while maintaining the rotational speed of the drive shaft 7 so as not to decrease, the rotational speed of the first motor / generator 2 and the clutch mechanism 6 are increased so that the rotational speed of the crankshaft 1a increases to a startable rotational speed Nes or higher. The engagement operation is controlled in a coordinated manner. Further, the first motor / generator 2 causes the engagement members 6a, the clutch member 6 to have a higher rotational speed than the engagement member 6b on the drive shaft 7 side of the clutch mechanism 6 while making the rotation speed of the engagement member 6a on the crank shaft 1a side. By sliding 6b, it is possible to engage without lowering the rotational speed of the drive shaft 7, and to prevent the engine 1 from sliding down when starting.

  As described above, when the rotation speed of the first motor / generator 2 and the engagement operation of the clutch mechanism 6 are coordinated and the clutch mechanism 6 is engaged, the clutch mechanism 6 is engaged. Further, since torque in the forward rotation direction is generated in the ring gear 5r and the drive shaft 7, a decrease in the torque of the drive shaft 7 due to engagement of the clutch mechanism 6 can be prevented. That is, it is possible to prevent the driving force from being insufficient when traveling uphill. Further, as described above, the clutch mechanism 6 is engaged while adjusting the rotational speed of the crankshaft 1a by the first motor / generator 2, thereby shortening the time required for the engagement of the clutch mechanism 6. be able to.

As shown in FIG. 7 and FIG. 10, when the rotational speed of the crankshaft 1a is increased to start the engine 1, the output torque of the second motor / generator 3 is Tm, and the second motor / generator The inertia torque of No. 3 is Im, the rotational change rate of the second motor / generator 3 is dωm / dt, the friction torque of the second motor / generator 3 is Tmf, and the speed reduction mechanism between the second motor / generator 3 and the differential 8 is Assuming that the gear ratio is Grm and the torque reduction rate due to slip when engaging the clutch mechanism 6 is Tfc, the shaft torque Tmp of the drive shaft 7 by the output of the second motor / generator 3 is:
Tmp = {Tm−Im · (dωm / dt) −Tmf} · Grm · Tfc (1)
It becomes. Also, assuming that the inertia torque of the engine 1 is Ie, the rate of change in rotation of the engine 1 is dωe / dt, and the friction torque of the engine 1 is Tef, the shaft torque Te of the carrier 5c to which the crankshaft 1a of the engine 1 is connected is
Te = − {Ie · (dωe / dt) + Tef} (2)
It becomes. Then, the inertia torque of the first motor / generator 2 is Ig, the rotational change rate of the first motor / generator 2 is dωg / dt, the friction torque of the first motor / generator 2 is Tgf, and the output of the first motor / generator 2 is output. If the shaft torque of the sun gear 5s generated by the above is Tg, the balance of the above-mentioned shaft torques Tmp, Te, Tg as shown in FIG.
Tg− {Ig · (dωg / dt) + Tgf} + Te + Tmp = 0 (3)
The following relational expression is obtained.

Therefore, as shown in FIG. 7, when the engine 1 is cranked while the rotation speed of the first motor / generator 2 is maintained at "0", and the rotation speed of the crankshaft 1a is increased, the first motor・ The shaft torque Tg generated by the output of the generator 2 can be calculated from the above formulas (1), (2) and (3).
Tg = -Tmp-Te + {Ig. (D.omega.g / dt) + Tgf}
= − {Tm−Im · (dωm / dt) −Tmf} · Grm · Tfc
+ {Ie · (dωe / dt) + Tef} + {Ig · (dωg / dt) + Tgf}
Can be obtained as

Then, as shown in FIG. 10, when the engine 1 is cranked by increasing the rotational speed of the first motor / generator 2 and the rotational speed of the crankshaft 1a is increased, the output of the first motor / generator 2 The shaft torque Tg to be generated is
Tg>-{Tm-Im. (D.omega.m / dt) -Tmf} .Grm.Tfc
+ {Ie · (dωe / dt) + Tef} + {Ig · (dωg / dt) + Tgf}
As a value satisfying the relational expression

  As described above, when the traveling state of the vehicle Ve is switched from the EV state to the HV state, when the rotation speed of the crankshaft 1a is synchronized with the startable rotation speed Nes in the above step S3 or step S4, or When the rotational speed of the crankshaft 1a is increased to a startable rotational speed Nes or more, the process proceeds to step S5, and the engine 1 is started in that state. For example, the engine 1 is started by igniting the engine 1 cranked at the startable rotation speed Nes or at a rotation speed equal to or higher than the startable rotation speed Nes or by injecting fuel. That is, the engine 1 enters an operation state in which autonomous rotation is possible, and the switching of the travel state from the EV state to the HV state is completed. Thereafter, this routine is once terminated.

  The flowchart of FIG. 11 shows another example of control by the “internal combustion engine starting means” in the present invention. In the control example shown in the flowchart of FIG. 6 described above, when the traveling state of the vehicle Ve is switched from the EV state to the HV state during uphill traveling, the rotation speed of the first motor / generator 2 and the engagement operation of the clutch mechanism 6 11 is a control in which the engine 1 is cranked to prevent the torque of the drive shaft 7 from being insufficient. On the other hand, the control example shown in the flowchart of FIG. When the driving state of the vehicle is switched from the EV state to the HV state, the clutch mechanism 6 is engaged by increasing the engagement pressure of the clutch mechanism 6 while maintaining the rotation speed of the first motor / generator 2 at “0”. Thus, the control is made to prevent the torque shortage of the drive shaft 7.

  That is, in FIG. 11, first, it is determined whether or not there is a switching request for the traveling state of the vehicle Ve (step S11). If there is still no request for switching the running state from the EV state to the HV state, and if a negative determination is made in this step S11, this routine is temporarily terminated without executing the subsequent control. On the other hand, when there is a request for switching the running state from the EV state to the HV state, if the determination in step S11 is affirmative, the process proceeds to step S12, and the driving force is increased while driving uphill. It is determined whether or not there is. The contents of control in steps S11 and S12 are the same as the contents of control in steps S1 and S2 in the control example shown in FIG.

  If the vehicle Ve is in a state where the driving force is increased when traveling uphill, if the determination in step S12 is affirmative, the process proceeds to step S13, where the engagement pressure of the clutch mechanism 6 is increased more than usual. The clutch mechanism 6 is engaged and the engine 1 is cranked. That is, in the control example shown in FIG. 11, the engine 1 is controlled by controlling the engagement operation of the clutch mechanism 6 while maintaining the rotational speed of the first motor / generator 2 as shown in FIG. Assuming control for cranking, when the clutch mechanism 6 is engaged, by increasing the engagement pressure, the clutch mechanism 6 is quickly engaged, and the drive shaft when the clutch mechanism 6 is engaged. 7 is prevented or suppressed. Accordingly, it is possible to prevent the driving force from being deficient when traveling uphill. Further, the time required for engaging the clutch mechanism 6 can be shortened.

  On the other hand, if the state of the vehicle Ve is not a state in which the driving force is increased when traveling uphill, and if a negative determination is made in step S12, the process proceeds to step S14, where the engagement pressure of the clutch mechanism 6 is normal. In this state, the engine 1 is cranked. When the vehicle Ve is not traveling on an uphill road, if the engagement pressure of the clutch mechanism 6 is increased and the clutch mechanism 6 is engaged, an engagement shock may occur during the engagement. In this case, the engagement operation of the clutch mechanism 6 is controlled as usual without increasing the engagement pressure of the clutch mechanism 6.

  In step S13 or step S14 as described above, when the clutch mechanism 6 is engaged and the rotation speed of the crankshaft 1a is synchronized with the startable rotation speed Nes, or the rotation speed of the crankshaft 1a can be started. If it will be in the state increased more than the rotation speed Nes, it will progress to step S15 and the engine 1 will be started in the state. That is, the engine 1 enters an operation state in which autonomous rotation is possible, and the switching of the travel state from the EV state to the HV state is completed. Thereafter, this routine is once terminated.

  As described above, according to the hybrid vehicle control device of the present invention, when the hybrid vehicle Ve is traveling on an uphill road, when the traveling state of the hybrid vehicle Ve is switched from the EV state to the HV state, that is, When the engine 1 is started in order to switch the running state to the HV state, the output of the first motor / generator 2 and the clutch mechanism so that the rotational speed of the crankshaft 1a increases while maintaining the rotational speed of the drive shaft 7. 6 engagement operations are controlled in coordination. Then, the engine 1 is started in a state where the rotational speed of the crankshaft 1a is increased to a startable rotational speed Nes that allows the engine 1 to rotate autonomously while the rotational speed of the drive shaft 7 is maintained. When the clutch mechanism 6 is engaged during traveling of the hybrid vehicle Ve, the torque of the drive shaft 6 may decrease due to the friction torque of the engine 1 or the like. As described above, the output of the first motor / generator 2 and the engagement / release operation of the clutch mechanism 6 are coordinated to increase the rotation speed of the crankshaft 1a and maintain the rotation speed of the drive shaft 7. The clutch mechanism 6 can be engaged while it is engaged. That is, it is possible to increase the rotational speed of the crankshaft 1a to the startable rotational speed Nes or more without lowering the torque of the drive shaft 7 and to make the clutch mechanism 6 engaged. For this reason, even when a large driving force is required during uphill traveling, a decrease in the torque of the drive shaft 7 is avoided, and the traveling state of the hybrid vehicle Ve is reduced without causing a shortage of driving force on the uphill road. It is possible to appropriately switch from the state to the HV state.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. Functional means for executing steps S4, S5 and steps S13, S15 correspond to "internal combustion engine starting means" in the present invention.

  In the above-described specific example, the hybrid vehicle that is the target of driving force control according to the present invention includes the engine 1 as the internal combustion engine, the first motor / generator 2 as the first electric motor, and the second motor / generator as the second electric motor. 3 and a power split mechanism 5 that distributes the power of the engine 1 to the drive wheels and the first motor / generator 2 has been described as an example. A hybrid vehicle that does not include the mechanism 5 may be used. In short, a so-called two-motor type hybrid comprising an internal combustion engine, a first electric motor, a second electric motor, and a clutch mechanism for connecting / disconnecting a power transmission path between the first electric motor and the second electric motor. A vehicle can be an object of control in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine (engine; ENG), 1a ... Crankshaft, 2 ... 1st electric motor (1st motor generator; MG1), 3 ... 2nd electric motor (2nd motor generator; MG2), 4 ... Drive wheel, DESCRIPTION OF SYMBOLS 5 ... Power split mechanism, 6 ... Clutch mechanism, 7 ... Drive shaft, 11 ... Electronic control unit (ECU), 12 ... Vehicle speed sensor, 13 ... Acceleration sensor, 14 ... Engine speed sensor, 15 ... Resolver, 16 ... Charge sensor 17 ... Accelerator opening sensor, 18 ... Inclination angle sensor, Ve ... Hybrid vehicle.

Claims (3)

Power transmission to the internal combustion engine, a first electric motor capable of increasing or decreasing the rotational speed of the crankshaft of the internal combustion engine by controlling the output, and the crankshaft and driving wheels by controlling the engagement / release operation A clutch mechanism capable of continuously connecting / disconnecting a torque transmission path to / from a drive shaft connected to the drive shaft and continuously changing a transmission torque capacity at the time of connection / disconnection; and direct power to the drive shaft A second electric motor capable of transmitting the power, and only the second electric motor is operated or only the first electric motor and the second electric motor are operated to generate driving force for traveling And a hybrid vehicle control device capable of selectively switching between a hybrid vehicle state in which the internal combustion engine is operated to travel,
When the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state when traveling on an uphill road or when a driving force increase is requested, the output of the first motor and the engagement / release operation of the clutch mechanism are coordinated. It is characterized by comprising an internal combustion engine starting means for starting the internal combustion engine in a state where the rotational speed of the crankshaft is increased while maintaining or decreasing the rotational speed of the drive shaft by controlling. A control device for a hybrid vehicle.   The internal combustion engine starting means starts the internal combustion engine in a state where the rotational speed of the crankshaft is increased to a predetermined startable rotational speed or more as a lower limit value of the rotational speed at which the internal combustion engine can autonomously rotate. The hybrid vehicle control device according to claim 1, further comprising means. The internal combustion engine and the first electric motor are connected so as to be able to transmit power to each other via a power split mechanism that divides the power of the internal combustion engine into the first electric motor and the drive wheels,
3. The control apparatus for a hybrid vehicle according to claim 1, wherein the clutch mechanism is provided between the power split mechanism and the drive shaft in the torque transmission path.

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