JP5866803B2 - Control device for hybrid vehicle - Google Patents

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 internal combustion engine is operated to run the vehicle. The present invention relates to a control device for a hybrid vehicle capable of traveling while switching between hybrid vehicle states.

  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 fuel consumption is improved while taking advantage of 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 is described 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

  In the invention described in Patent Document 1, when the motoring of the engine is performed, that is, when the engine is started, the power adjustment device by the coupling mechanism and the electric motor are separated. That is, power transmission between the output shaft of the engine and the drive shaft is interrupted. Therefore, according to the invention described in Patent Document 1, when starting the engine, it is possible to avoid transmission of torque fluctuations of the engine generated at that time to the drive shaft. That is, it is said that drivability can be improved.

  However, in the invention described in Patent Document 1, as described above, a coupling mechanism such as a clutch or a brake is released when the engine is started in order to avoid transmission of torque fluctuations when the engine is started to the drive shaft. However, the case where the released clutch or the like is re-engaged is not considered. For example, when the clutch is released when the engine is started and the clutch is engaged again after the engine is started, it may take time to switch the traveling state of the hybrid vehicle that accompanies the start of the engine. Further, an engagement shock occurs when the clutch or the like is engaged after the engine is started, and as a result, the drivability of the hybrid vehicle may be reduced. Furthermore, motoring is performed for starting the engine, that is, cranking is performed for starting the engine by driving the motor, so that power consumption for driving the motor at that time increases. .

  Thus, for example, when the driving state of the hybrid vehicle is switched from the electric vehicle state in which only the electric motor is operated to the hybrid vehicle state in which the internal combustion engine is operated to travel, the hybrid vehicle with the start of the internal combustion engine is switched. There is still room for improvement in order to quickly switch the driving state without reducing drivability.

  The present invention has been made paying attention to the technical problem described above, and changes the traveling state of the hybrid vehicle from the electric vehicle state in which only the electric motor is operated to the hybrid vehicle state in which the internal combustion engine is operated to travel. An object of the present invention is to provide a control device for a hybrid vehicle that can be switched quickly and smoothly and that can suppress power consumption when starting an internal combustion engine.

In order to achieve the above object, the invention of claim 1 is directed to an internal combustion engine, a first electric motor capable of adjusting an output shaft rotational speed of the internal combustion engine by controlling an output, and the internal combustion engine. A clutch mechanism capable of connecting / disconnecting a torque transmission path to / from a drive wheel and continuously changing a transmission torque capacity at the time of connection / disconnection; and transmitting power directly to the drive wheel A second electric motor capable of operating an electric vehicle in which only the second electric motor or only the first electric motor and the second electric motor are operated to generate a driving force for traveling; and the internal combustion engine is operated. In a hybrid vehicle control device capable of selectively switching between traveling hybrid vehicle states, the transmission torque capacity is gradually increased by operating the clutch mechanism. While connecting the torque transmission path, the first starting means for starting the internal combustion engine by increasing the output shaft rotational speed and the clutch mechanism are operated to gradually increase the transmission torque capacity. by increasing the output speed of the first motor while connecting the torque transmission path, and a second start means for starting said internal combustion engine by raising the output shaft rotational speed, the hybrid vehicle is the clutch mechanism If the switching to the hybrid vehicle state is required when running at opened front SL electric state of the vehicle is operated only the second electric motor in a state, on the basis of the vehicle speed and the longitudinal acceleration of the hybrid vehicle Either the first starting means or the second starting means is selected, and the internal combustion engine is started by the selected starting means. And by a control apparatus characterized by comprising a driving state switching means for switching the traveling state to the hybrid vehicle state.

  In the invention of claim 2, in the invention of claim 1, the first starting means and the second starting means are both predetermined as lower limit values 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 in which the output shaft rotational speed is increased to be equal to or higher than the startable rotational speed.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the travel state switching means is such that the vehicle speed exceeds a startable vehicle speed set in advance as a lower limit value of a vehicle speed at which the internal combustion engine can be started. In addition, the control device includes means for starting the internal combustion engine with the first starting means when the longitudinal acceleration is a positive value.

  According to a fourth aspect of the invention, there is provided a startable vehicle speed according to any one of the first to third aspects, wherein the traveling state switching means sets the vehicle speed as a lower limit range of a vehicle speed at which the internal combustion engine can be started. When the vehicle speed is within the startable vehicle speed range and the longitudinal acceleration is a positive value, the running state is determined by starting the internal combustion engine with the first starting means. When the vehicle speed is within the startable vehicle speed range and the longitudinal acceleration is a value of 0 or less, and when the vehicle speed is less than or equal to the startable vehicle speed range, the second start is performed. The control device includes means for switching the traveling state to the hybrid vehicle state by starting the internal combustion engine by means.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, 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. It is connected so as to be able to transmit power to each other via a power split mechanism, and the clutch mechanism is provided between the power split mechanism and the drive wheel in the torque transmission path, It is a control device.

  According to the first aspect of the invention, when the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state, that is, when the internal combustion engine is started to switch the traveling state to the hybrid vehicle state, the hybrid vehicle at that time On the basis of the vehicle speed and the longitudinal acceleration, either the first starting means or the second starting means is appropriately selected to start the internal combustion engine. Therefore, the internal combustion engine can be appropriately started by an appropriate method / means according to the level of the vehicle speed during traveling and the magnitude of the longitudinal acceleration. That is, when the first starting means is selected, the internal combustion engine is started by increasing the output shaft rotational speed of the internal combustion engine by the power transmitted from the drive wheel without using an electric motor or a dedicated starter motor. Even when the second starting means is selected, the output shaft rotation speed is increased by the output of the first electric motor after the output shaft rotation speed of the internal combustion engine is increased to some extent by the power transmitted from the drive wheel side in advance. The number can be increased and the internal combustion engine can be started. Therefore, the driving state of the hybrid vehicle can be switched quickly and smoothly without reducing drivability, and the power consumption when starting the internal combustion engine to switch the driving state can be suppressed. .

  According to the invention of claim 2, the rotational speed of the output shaft of the internal combustion engine is capable of autonomous rotation of the internal combustion engine when the internal combustion engine is started by either the first starting means or the second starting means. The engine speed is increased beyond the startable rotation speed and the state is maintained. 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 first starting means or the second starting means.

  Further, according to the invention of claim 3, when the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state, when the vehicle speed of the hybrid vehicle exceeds the startable vehicle speed and the longitudinal acceleration is a positive value, In other words, the internal combustion engine is started by the first starting means when the hybrid vehicle is traveling at a speed higher than the startable vehicle speed and is further accelerating. That is, by gradually increasing the transmission torque capacity between the internal combustion engine and the drive wheels by the clutch mechanism, the output shaft speed is increased and the internal combustion engine is started. When the internal combustion engine is started, it is necessary to crank the internal combustion engine. While the hybrid vehicle is traveling, the transmission torque capacity of the clutch mechanism is increased to transmit the torque from the drive wheels to the internal combustion engine. The internal combustion engine can be cranked without being driven by a dedicated starter motor or the like. During such cranking, torque fluctuations occur in the power transmission path from the drive wheels to the internal combustion engine, but in addition to the hybrid vehicle traveling at a speed higher than the startable vehicle speed, Since it is a condition, it is less susceptible to the influence of torque fluctuation at the start than when the internal combustion engine is started during constant speed traveling or decelerating traveling. Therefore, according to the third aspect of the present invention, the internal combustion engine can be started without consuming electric power for cranking the internal combustion engine as described above, and drivability due to torque fluctuation at the start can be improved. The decrease can be suppressed.

  According to the invention of claim 4, when the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state, the vehicle speed of the hybrid vehicle exceeds the startable vehicle speed range, and the vehicle speed of the hybrid vehicle is When the vehicle is within the startable vehicle speed range and is accelerating, the internal combustion engine is started by the first starting means. That is, by gradually increasing the transmission torque capacity between the internal combustion engine and the drive wheels by the clutch mechanism, the output shaft speed is increased and the internal combustion engine is started. Further, when the vehicle speed of the hybrid vehicle is less than or equal to the startable vehicle speed range, and when the vehicle speed of the hybrid vehicle is within the startable vehicle speed range and is decelerating, the internal combustion engine is started by the second starter. That is, the clutch mechanism is gradually engaged, and the output shaft speed is increased by the output of the first electric motor, so that the internal combustion engine is started. Therefore, when the traveling state of the hybrid vehicle is switched from the electric vehicle state to the hybrid vehicle state, depending on the level of the vehicle speed during traveling and the magnitude of the longitudinal acceleration, a more appropriate means such as the first starting means or the second starting means is used. The internal combustion engine can be started. Therefore, the driving state of the hybrid vehicle can be switched quickly and smoothly without reducing drivability. In addition, it is possible to suppress power consumption when starting the internal combustion engine in order to switch the traveling state of the hybrid vehicle.

  According to the invention of claim 5, the power split mechanism for distributing the power output from the internal combustion engine to the first 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, switching of the traveling state of the hybrid vehicle can be switched quickly and smoothly without reducing drivability. In addition, it is possible to suppress power consumption when starting the internal combustion engine in order to switch the running state.

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. FIG. 7 is a collinear diagram for explaining a behavior when the control shown in the flowchart of FIG. 6 is executed, a startable rotation speed of the internal combustion engine considered at that time, and the like. FIG. 7 is a schematic diagram for explaining a startable vehicle speed, a startable vehicle speed range, and the like that are considered when executing the control shown in the flowchart of FIG. 6. FIG. 7 is a diagram for explaining the behavior when the control shown in the flowchart of FIG. 6 is executed, and is particularly a collinear diagram for explaining the behavior when executing the running state switching control by the “first starter”. It is. FIG. 7 is a diagram for explaining the behavior when executing the control shown in the flowchart of FIG. 6, and particularly for explaining the behavior when executing the running state switching control by the “second starting means”. It is. FIG. 7 is a diagram for explaining the behavior when the running state switching control by the “second starter” shown in the flowchart of FIG. 6 is executed, and particularly the behavior when the shaft torque by the output of the second motor is positive. It is an alignment chart for explaining. FIG. 7 is a diagram for explaining the behavior when the running state switching control by the “second starter” shown in the flowchart of FIG. 6 is executed, particularly when the shaft torque torque by the output of the second motor is negative. FIG.

  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 output shaft 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 gears described later are connected to the ring gear 5r. Via the transmission mechanism 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 output shaft 1a of the engine 1 changes according to the rotational speed of the first motor / generator 2. Therefore, the output shaft speed of the engine 1 can be controlled by controlling the output of the first motor / generator 2.

  The clutch mechanism 6 is an engagement device for connecting and disconnecting the torque transmission path between the engine 1 and the drive wheel 4, and is provided between the ring gear 5 r of the power split mechanism 5 and the gear transmission mechanism 7. ing. 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. Accordingly, the clutch mechanism 6 can connect / disconnect the torque transmission path between the engine 1 and the drive wheel 4 and continuously change the transmission torque capacity when connecting / disconnecting the torque transmission path. It has a possible configuration.

  The gear transmission mechanism 7 includes a drive gear 7a connected to the ring gear 5r through the clutch mechanism 6 as described above, a driven gear 7b meshing with the drive gear 7a, a coaxial gear with the driven gear 7b, and a differential gear described later. The counter gear 7c meshes with the ring gear 8a, and the driven gear 7d meshes with the drive gear 9 provided on the output shaft 3a of the second motor / generator 3 described later.

  As described above, the differential 8 has the ring gear 8 a meshed with the counter gear 7 c of the gear transmission mechanism 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 gear transmission mechanism 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 the power by interposing the power split mechanism 5 with the drive wheel 4, whereas the second motor / generator 3 is configured to transmit power. The power can be directly transmitted to and from the drive wheel 4. That is, in the second motor / generator 3, the drive gear 9 that rotates integrally with the output shaft 3a is attached to the output shaft 3a as described above, and the drive gear 9 is connected to the driven gear 7d of the gear transmission mechanism 7. I'm engaged. Therefore, the second motor / generator 3 is connected to the drive wheels 4 through the drive gear 9, the gear transmission mechanism 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 device 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 rotation speed of the output shaft 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, and Detection signals from various sensor devices such as an accelerator opening sensor 17 for detecting a driver's accelerator operation by an accelerator pedal or an accelerator lever are input. 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 the second motor / generator 3 is operated, or the first motor / generator 2 is operated. And only the second motor / generator 3 is operated (that is, the engine 1 is not operated), and an electric vehicle (EV) state that generates driving torque for running the vehicle Ve, and a state where the engine 1 is operated It is possible to selectively switch between the hybrid vehicle (HV) state in which the vehicle Ve is traveling.

  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 the running state is switched from the EV state to the HV state, it is necessary to start the stopped engine 1, but when starting the engine 1, as described above, torque fluctuations are inevitably generated. As a result, the drivability of the vehicle Ve may be reduced.

  Therefore, in the control device for the hybrid vehicle Ve according to the present invention, the running state can be switched from the EV state to the HV state quickly and smoothly without reducing drivability, and the engine 1 is started. The following control is performed so that the power consumption during the operation can be suppressed. 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 vehicle speed V of the vehicle Ve at that time is It is determined whether or not the threshold value T is larger than a value obtained by adding a predetermined value α.

  Here, the threshold value T is a value set in advance as a startable vehicle speed that is a lower limit value of the vehicle speed at which the engine 1 can be started. As shown in FIG. 7, for the engine 1, a startable rotation speed Nes that is a lower limit value of the rotation speed at which the engine 1 can autonomously rotate is obtained in advance. Is a reference value determined and set in advance as a vehicle speed at which the engine speed becomes equal to or greater than the startable engine speed Nes. Therefore, when the vehicle speed V exceeds the threshold T, that is, the startable vehicle speed, it can be determined that the rotational speed of the engine 1 exceeds the startable rotational speed Nes, and it is determined that the engine 1 can be started. Can do.

As shown in FIG. 7, the rotation speed of the ring gear 5r when the rotation speed of the engine 1, that is, the rotation speed of the carrier 5c becomes the startable rotation speed Nes, is set as the startable ring gear rotation speed Np. Here, if the ratio between the gear ratio between the sun gear 5s and the carrier 5c and the gear ratio between the carrier 5c and the ring gear 5r is “1: ρ”, the startable rotation speed Nes and the startable The relationship with the ring gear speed Np is
Nes: Np = 1: 1 + ρ (1)
Represented as: Therefore, from equation (1), the startable ring gear rotation speed Np is
Np = (1 + ρ) ・ Nes (2)
It becomes. When the vehicle speed is V, the tire radius of the drive wheel 4 is Rt, the differential gear ratio of the differential 8 is Gr, and K is a constant, the startable ring gear rotation speed Np is
Np = K ・ V ・ Rt ・ Gr (3)
Represented as: Therefore, from the equations (2) and (3), the startable vehicle speed, that is, the threshold value T is: T = K · (1 + ρ) · Nes · Rt / Gr (4)
Can be obtained as

  Further, the predetermined value α is a value set to determine a startable vehicle speed range R that is a lower limit range of the vehicle speed at which the engine 1 can be started. As will be described later, the predetermined value α is a clutch for starting the engine 1. This value is set in advance in consideration of the decrease in vehicle speed that decreases when the mechanism 6 is engaged. Therefore, as shown in FIG. 8, the vehicle speed range from “threshold value T” to “threshold value T + predetermined value α” is a startable vehicle speed range R set in advance as a lower limit range of vehicle speed at which engine 1 can be started. It has become.

  If the vehicle speed V is greater than “threshold value T + predetermined value α”, that is, the vehicle speed V exceeds the startable vehicle speed range R, the process proceeds to step S3 when an affirmative determination is made in step S2. In other words, this case is the situation indicated by case A in FIGS. In step S3, the traveling state of the vehicle Ve is switched from the EV state to the HV state with the rotation speed of the first motor / generator 2 maintained at zero. This is switching control of the running state by the “first starter” in the present invention, and gradually increases the transmission torque capacity of the clutch mechanism 6 to connect the torque transmission path between the engine 1 and the drive wheels. This is the control to increase the rotational speed of the engine 1.

  Specifically, as shown in FIG. 9, 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 rotation speed at zero. As a result, the rotational speed of the output shaft 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 output shaft 1a can be increased to the startable rotational speed Nes or higher.

  On the other hand, if the vehicle speed V is equal to or less than “threshold value T + predetermined value α”, a negative determination is made in step S2, the process proceeds to step S4, whether the vehicle speed V is greater than the threshold value T, that is, It is then determined whether or not the vehicle speed V exceeds the startable vehicle speed. If the vehicle speed V is less than or equal to the threshold T, that is, if the vehicle speed V is less than the startable vehicle speed, a negative determination is made in step S4, the process proceeds to step S5. That is, this case is a situation indicated by case C in FIGS. In step S5, the rotational speed of the first motor / generator 2 is increased, and the traveling state of the vehicle Ve is switched from the EV state to the HV state. This is switching control of the running state by the “second starter” in the present invention, and gradually increases the transmission torque capacity of the clutch mechanism 6 to connect the torque transmission path between the engine 1 and the drive wheels. Thus, the rotation speed of the engine 1 is increased and the rotation speed of the engine 1 is also increased by the first motor / generator 2.

  Specifically, as in the case of the “first starter” described above, 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. As shown in FIG. 10, in this “second starting means”, the first motor / generator 2 is subjected to power running control so that the rotational speed of the output shaft 2a, that is, the sun gear 5s increases in the forward rotation direction. As a result, the rotational speed of the output shaft 1a of the engine 1 connected to the carrier 5c is increased in the forward rotation direction. Therefore, by controlling so that the transmission torque capacity of the clutch mechanism 6 gradually increases, the rotational speed of the engine 1 is increased to some extent in advance, and further, the rotational speed of the engine 1 is increased by the output of the first motor / generator 2. As a result, the engine 1 can be cranked and the rotational speed of the output shaft 1a can be increased to the startable rotational speed Nes or higher.

  As described above, when the vehicle speed V is equal to or lower than the startable vehicle speed, even if the clutch mechanism 6 is engaged and the rotational speed of the engine 1 is increased by the torque from the drive wheel 4 side, the rotational speed of the engine 1 is started. Since the engine speed cannot be increased beyond the possible rotational speed Nes, the first motor / generator 2 is controlled to increase the rotational speed of the engine 1 by performing power running control.

  On the other hand, if the vehicle speed V is greater than the threshold value T, that is, if the vehicle speed V exceeds the startable vehicle speed, an affirmative determination is made in step S4, the process proceeds to step S6. That is, this case is a situation shown by case B in FIGS. In step S6, it is determined whether the longitudinal acceleration dV / dt of the vehicle Ve at that time is 0 or less. The situation shown in case B is a case where the vehicle speed V is equal to or less than “threshold value T + predetermined value α” and is greater than the threshold value T, that is, the vehicle speed V is a value within the startable vehicle speed range R. It is. In this case, since the vehicle speed V is larger than the threshold value T, the rotational speed of the engine 1 of the engine 1 is increased to the startable rotational speed Nes or higher by engaging the clutch mechanism 6, that is, by the "first starting means". Can be made.

  However, when the clutch mechanism 6 is engaged, the rotational speeds of the ring gear 5r and the engine 1 are inevitably decreased, and the vehicle speed V is also decreased accordingly. Such a decrease in the rotational speed of the engine 1 or the vehicle speed V may give a shock or a sense of incongruity to the driver and may affect the drivability of the vehicle Ve. The effect becomes significant when the vehicle Ve is traveling at a constant speed or when traveling at a reduced speed. Therefore, in step S6, the vehicle Ve is selected in order to appropriately select the “first starter” and the “second starter” according to the state of the vehicle Ve, and to switch the running state and start the engine 1. The longitudinal acceleration dV / dt of the vehicle is detected, and it is determined whether the vehicle Ve is traveling at an accelerated speed, traveling at a constant speed, or traveling at a reduced speed.

  When the vehicle Ve is running at an accelerated speed, even if the clutch mechanism 6 is slip-engaged, the decrease in the rotational speed of the engine 1 is small compared to when the vehicle Ve is running at a constant speed or at a reduced speed. It is unlikely to affect drivability. Therefore, if the longitudinal acceleration dV / dt of the vehicle Ve is greater than 0, that is, if the vehicle Ve is traveling at an accelerated speed and the determination is negative in step S6, the process proceeds to step S3 described above. That is, this case is a situation indicated by case B1 in FIGS. In steps S3 and S7, switching of the running state and starting of the engine 1 are executed by the “first starting means” similar to the above.

  On the other hand, when the vehicle Ve is traveling at a constant speed or traveling at a reduced speed, when the clutch mechanism 6 is slip-engaged, the rotational speed of the engine 1 is greatly reduced, which may affect drivability. Becomes larger. Therefore, when the longitudinal acceleration dV / dt of the vehicle Ve is 0 or less, that is, when the vehicle Ve is traveling at a constant speed or traveling at an acceleration, affirmative determination is made in step S6, the above-described steps Proceed to S5. That is, this case is a situation indicated by case B2 in FIGS. In steps S5 and S7, the switching of the running state and the starting of the engine 1 are executed by the “second starting means” as described above. In the case B2 as described above, the increase of the rotational speed of the engine 1 due to the engagement of the clutch mechanism 6 is minimized by switching the running state and starting the engine 1 by the “second starting means”. The rotational speed of the engine 1 can be increased to the startable rotational speed Nes or higher by the output of the first motor / generator 2. Therefore, it is possible to minimize a decrease in the rotational speed of the engine 1 and a decrease in the vehicle speed V when the clutch mechanism 6 is engaged, and to prevent or suppress a decrease in drivability.

As shown in FIGS. 9, 11, and 12, the output torque of the second motor / generator 2 is increased when the engine speed is increased by the “first starter” and the “second starter”. Tm, the inertia torque of the second motor / generator 3 is Im, the rotation rate of the second motor / generator 3 is dωm / dt, the friction torque of the second motor / generator 3 is Tmf, the second motor / generator 3 and the differential 8 If the gear ratio of the speed reduction mechanism is Grm and the torque reduction rate due to slip when the clutch mechanism 6 is engaged is Tfc, the shaft torque Tmp of the gear transmission mechanism 7 by the output of the second motor / generator 3 is ,
Tmp = {Tm−Im · (dωm / dt) −Tmf} · Grm · Tfc (4)
It becomes. Further, 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 output shaft 1a of the engine 1 is connected is
Te = − {Ie · (dωe / dt) + Tef} (5)
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 (6)
The following relational expression is obtained.

Therefore, when the engine 1 is cranked by the “first starter” as shown in FIG. 9 and its rotational speed is increased, the shaft torque Tg generated by the output of the first motor / generator 2 is the above ( From 4), (5), and (6),
Tg = -Tmp-Te + {Ig. (D.omega.g / dt) + Tgf}
= − {Tm−Im · (dωm / dt) −Tmf} · Grm · Tfc
+ {Ie · (dωe / dt) + Tef} + {Ig · (dωg / dt) + Tgf}
(7)
Can be obtained as

The shaft torque Tg generated by the output of the first motor / generator 2 when the engine 1 is cranked by the “second starting means” as shown in FIGS.
Tg>-{Tm-Im. (D.omega.m / dt) -Tmf} .Grm.Tfc
+ {Ie · (dωe / dt) + Tef} + {Ig · (dωg / dt) + Tgf}
(8)
As a value satisfying the relational expression At this time, as shown in FIG. 11, when the shaft torque Tmp is “Tm> 0”, that is, when the rotation direction of the shaft torque Tmp is the normal rotation direction, and as shown in FIG. <0 ”, that is, the rotational direction of the shaft torque Tmp may be the reverse direction, but the case where the shaft torque Tmp is“ Tm <0 ”is greater than the case where the shaft torque Tmp is“ Tm> 0 ”. Also, the value of the shaft torque Tg increases.

  As described above, when the traveling state of the vehicle Ve is switched from the EV state to the HV state, in step S3 or step S5, that is, by the “first starter” or “second starter” in the present invention, When the rotational speed is increased to the startable rotational speed Nes or more, the process proceeds to step S7, and the engine 1 is started. For example, the engine 1 is started by igniting the engine 1 that is cranked 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.

  As described above, according to the hybrid vehicle control device of the present invention, when the traveling state of the hybrid vehicle Ve is switched from the EV state to the HV state, that is, the engine 1 is started to switch the traveling state to the HV state. In this case, based on the vehicle speed V and the longitudinal acceleration dV / dt of the hybrid vehicle Ve at that time, either the “first starter” or the “second starter” is appropriately selected and the engine 1 is started. For example, when the vehicle speed V exceeds the startable vehicle speed range R, and when the vehicle speed V is a value within the startable vehicle speed range R and the vehicle is accelerating, the engine 1 is started by the “first starter”. Is done. That is, by gradually engaging the clutch mechanism 6 and gradually increasing its transmission torque capacity, the engine 1 is cranked and the rotational speed of the output shaft 1a is increased. Then, the engine 1 is started in a state where the rotation speed of the output shaft 1a is increased to the startable rotation speed Nes or higher.

  Further, when the vehicle speed V is a value less than or equal to the startable vehicle speed range R, and when the vehicle speed V is a value within the startable vehicle speed range R and the vehicle is decelerating, the engine 2 is driven by the “second starter”. Is started. That is, the clutch mechanism 6 is gradually engaged, and the engine 1 is cranked by the output of the first motor / generator 2 to increase the rotational speed of the output shaft 1a. Then, the engine 1 is started in a state where the rotation speed of the output shaft 1a is increased to the startable rotation speed Nes or higher.

  Therefore, when the traveling state of the hybrid vehicle Ve is switched from the EV state to the HV state, the “first starting unit” and the “second starting unit” are selected depending on the level of the vehicle speed V and the longitudinal acceleration dV / dt during traveling. The engine 1 can be started by a more appropriate means. That is, when the vehicle speed V during traveling in the EV state is sufficiently high and “first starter” is selected because the vehicle is accelerating, power is not used to crank the engine 1. In addition, by simply controlling the slip engagement state of the clutch mechanism 6, the engine 1 can be started by easily increasing the rotational speed of the output shaft 1a by the power transmitted from the drive wheel 4 side. Therefore, it is possible to reduce power consumption when starting the engine 1 in order to switch the traveling state from the EV state to the HV state, and it is possible to quickly and smoothly switch the traveling state.

  On the other hand, when the “second starting means” is selected because the vehicle speed V during traveling in the EV state is low and the vehicle is traveling at a constant speed or decelerating, output is made by the power transmitted from the drive wheel 4 side in advance. After increasing the rotational speed of the shaft 1a to some extent, the engine 1 can be started by increasing the rotational speed of the output shaft 1a to the startable rotational speed Nes or higher by the output of the first motor / generator 2. Therefore, when the vehicle speed V is low, or the vehicle is running at a constant speed or decelerating, there is a possibility that the rotational speed of the engine 1 or the vehicle speed V may be greatly reduced by engaging the clutch mechanism 6. Even if it exists, the fall of the drivability by the rotation speed of the engine 1 and the vehicle speed V falling can be prevented or suppressed.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means for executing steps S3 and S7 corresponds to the “first starting means” in the present invention, and executes steps S5 and S7. The functional means to perform corresponds to the “second starting means” in the present invention. The functional means for executing steps S2 to S6 corresponds to the “running state switching means” in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine (engine; ENG), 1a ... Output shaft, 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, 11 ... Electronic control unit (ECU), 12 ... Vehicle speed sensor, 13 ... Acceleration sensor, 14 ... Engine speed sensor, 15 ... Resolver, 16 ... Charge sensor, 17 ... Accelerator opening Degree sensor, Ve ... Hybrid vehicle.

Claims (5)

The internal combustion engine, a first electric motor capable of adjusting the output shaft rotational speed of the internal combustion engine by controlling the output, and a torque transmission path between the internal combustion engine and the drive wheel are connected and disconnected, and A clutch mechanism capable of continuously changing a transmission torque capacity at the time of connection / disconnection, and a second electric motor capable of directly transmitting power to the drive wheels, wherein only the second electric motor or the Traveling by selectively switching between an electric vehicle state in which only the first electric motor and the second electric motor are operated to generate driving force for traveling and a hybrid vehicle state in which the internal combustion engine is operated to travel In a possible hybrid vehicle control device,
First starting means for starting the internal combustion engine by increasing the output shaft rotational speed by connecting the torque transmission path while gradually increasing the transmission torque capacity by operating the clutch mechanism;
By connecting the torque transmission path while gradually increasing the transmission torque capacity by operating the clutch mechanism and increasing the output rotational speed of the first motor, the output shaft rotational speed is increased and the internal combustion engine is increased. A second starting means for starting the engine;
If the hybrid vehicle is the switching to the hybrid vehicle state is required when running at pre SL electric state of the vehicle is operated only the second electric motor in a state of opening the clutch mechanism, the hybrid vehicle The driving state is switched to the hybrid vehicle state by selecting either the first starting means or the second starting means based on the vehicle speed and the longitudinal acceleration, and starting the internal combustion engine with the selected starting means. A control apparatus for a hybrid vehicle, comprising: a traveling state switching unit.   The first starter and the second starter are both in a state in which the output shaft rotational speed is increased above a startable rotational speed that is predetermined 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 for starting the internal combustion engine.   The traveling state switching means is configured to perform the first start when the vehicle speed exceeds a startable vehicle speed that is predetermined as a lower limit value of the vehicle speed at which the internal combustion engine can be started and the longitudinal acceleration is a positive value. The hybrid vehicle control device according to claim 1, further comprising means for starting the internal combustion engine.   The traveling state switching means is configured such that the vehicle speed exceeds a startable vehicle speed range set in advance as a lower limit range of the vehicle speed at which the internal combustion engine can be started, and the vehicle speed is within the startable vehicle speed range and the front and rear When the acceleration is positive, the internal combustion engine is started by the first starting means to switch the traveling state to the hybrid vehicle state, the vehicle speed is within the startable vehicle speed range, and the longitudinal acceleration is When the vehicle speed is less than or equal to 0 and the vehicle speed is less than or equal to the startable vehicle speed range, the traveling state is switched to the hybrid vehicle state by starting the internal combustion engine with the second starting means. 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,
5. The control device for a hybrid vehicle according to claim 1, wherein the clutch mechanism is provided between the power split mechanism and the drive wheel in the torque transmission path. 6.

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