JP2006207686A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle, wherein an increase of power consumption and the degradation of a life is suppressed by eliminating frequent operation of changing over a power dividing mechanism between an operated condition and a non-operated condition. <P>SOLUTION: The hybrid vehicle uses a planetary gear unit 14 as the power dividing mechanism for transmitting the output power of a DE 11 to a driving wheel 15 and a MG 13 and for transmitting the output power of a MG 12 to the driving wheel 15. It also uses a lock mechanism 50 for fixing the rotation of the MG 13 to permit change-over of the planetary gear unit 14 between the operated condition and the non-operated condition. When a change amount ΔPe<SB>(n)</SB>of engine required output is lower than a reference change amount ΔPe<SB>(base)</SB>or a change amount ΔSpeed<SB>(n)</SB>of a vehicle speed is lower than a reference change amount ΔSpeed<SB>(base)</SB>, the lock of the MG 13 by the lock mechanism 50 is executed to change over the planetary gear unit 14 into the non-operated condition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hybrid vehicle that can run using an engine and an electric motor as a power source.

  In recent years, a hybrid vehicle has been proposed that is equipped with an engine that outputs torque by the combustion of fuel and an electric motor that outputs torque by supplying electric power, and can travel by transmitting the torque of the engine and the electric motor to wheels. Has been. In such a hybrid vehicle, driving and stopping of the engine and the electric motor are controlled according to the driving state, so that the wheel is driven only by the torque of the electric motor, or the wheel is driven by the torque of both the engine and the electric motor. The electric motor can be driven by the electric power stored in the battery. When the energy of the battery decreases, the engine is driven to charge the battery.

  That is, in the hybrid vehicle, an engine and an electric motor are provided as driving force sources, and a planetary gear that combines the power of the engine and the electric motor and transmits it to the wheels is provided. Specifically, the output shaft of the engine is connected to the planetary gear carrier, the output shaft of the electric motor is connected to the ring gear of the planetary gear, and power is transmitted from the sprocket connected to the ring gear to the wheels. It is configured. A generator is provided between the planetary gear and the engine, and the rotating shaft of the generator is connected to the sun gear of the planetary gear. Therefore, the engine power is divided into wheels and a generator by the planetary gear, and the engine rotation speed can be controlled by controlling the rotation speed of the generator. That is, the power split mechanism constituted by the planetary gears has a function of converting the rotational speed of the engine and a function of splitting the engine power into wheels and a generator.

  In the hybrid vehicle configured as described above, in steady running, the vehicle is mainly driven by an engine, and power generation by the generator is minimized, that is, the rotational speed is reduced in order to increase efficiency. In this case, it is desirable to fix the rotation of the generator with a brake in order to improve fuel consumption. However, if the rotation of the generator is suddenly fixed in this way, the impact is transmitted to the vehicle and drivability is reduced. As what solves such a problem, there exists a thing described in the following patent document 1, for example.

  The hybrid vehicle described in Patent Document 1 can be switched between a non-generator mode in which the generator is stopped by a brake and a power generation mode in which the brake is released, and the brake is applied after the generator rotational speed approaches zero. By engaging, the shock at the time of engagement is reduced.

Japanese Patent Laid-Open No. 9-156387

  In the hybrid vehicle of Patent Document 1 described above, when the accelerator opening is 20% or less and the actual rotational speed of the generator becomes smaller than the rotational speed allowable value with which the brake can be engaged, Are engaged. That is, regardless of the traveling state of the hybrid vehicle, the brake is always engaged when the actual rotational speed of the generator becomes smaller than the allowable rotational speed. By the way, even if the hybrid vehicle is in a traveling state in which acceleration and deceleration are repeated, the accelerator opening may be temporarily 20% or less, and the actual rotational speed of the generator may be smaller than the allowable rotational speed. 1, even in this case, the brake is engaged. However, in such a traveling state, the accelerator opening immediately exceeds 20% or the actual rotational speed of the generator exceeds the allowable rotational speed, and the brake is released. To be implemented. Therefore, problems such as an increase in power consumption and a decrease in life due to frequent operation of the brake occur.

  The present invention is for solving such a problem, and eliminates frequent switching operation between an operating state and a non-operating state in a power split mechanism, and suppresses an increase in power consumption and a decrease in service life. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a hybrid vehicle of the present invention includes an engine, a generator capable of generating power using at least a part of the output of the engine, and power supply from the generator. An electric motor that can receive and rotate; a power split mechanism that transmits power from the engine to the drive wheels and the generator; and a power split mechanism that transmits power from the electric motor to the drive wheels; and the power split mechanism is in an operating state. Switching means for switching to the non-operating state, driving state detecting means for detecting the driving state of the hybrid vehicle, and the power split mechanism by the switching means when the stable running state of the hybrid vehicle is detected by the driving state detecting means And a control means for switching to a non-operating state.

  In the hybrid vehicle of the present invention, the control means determines that the hybrid vehicle is in the stable running state when the amount of change in the output of the hybrid vehicle is equal to or less than a predetermined value set in advance. .

  According to the hybrid vehicle of the present invention, the power output from the engine is transmitted to the drive wheels and the generator by the power split mechanism, and the power output from the electric motor can be transmitted to the drive wheels. When the control means detects the stable running state of the hybrid vehicle from the detection result of the driving state detection means, the power split mechanism is switched to the non-operation state by the switching means. By switching the power split mechanism to the non-operating state only when the vehicle is in a stable running state where acceleration and deceleration are not repeated, frequent switching operations between the operating state and the non-operating state in the power split mechanism are eliminated, and the switching means is operated. An increase in power consumption can be suppressed and the life of the switching means can be extended.

  Embodiments of a hybrid vehicle according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention, FIG. 2 is a collinear diagram showing driving forces of a generator, an engine, and an electric motor in the hybrid vehicle, and FIG. It is a flowchart showing the output control by a hybrid vehicle.

  In the hybrid vehicle of this embodiment, as shown in FIG. 1, a diesel engine (DE) 11 and a motor generator (MG) 12 as an electric motor are mounted on the vehicle as a power source. In addition, a motor generator (MG) 13 that receives the output of DE 11 and generates electric power is also mounted. These DE11, MG12, and MG13 are connected by a power split mechanism 14. The power split mechanism 14 distributes the output of the DE 11 to the MG 13 and the drive wheel 15 and transmits the output from the MG 12 to the drive wheel 15 or to the drive wheel 15 via the speed reducer 16 and the drive shaft 17. It functions as a transmission related to the driving force.

  MG12 is an AC synchronous motor and is driven by AC power. The inverter 18 converts the electric power stored in the battery 19 from DC to AC and supplies it to the MG 12, and converts the electric power generated by the MG 13 from AC to DC and stores it in the battery 19. The MG 13 has basically the same configuration as the MG 12 described above, and has a configuration as an AC synchronous motor. In this case, the MG 12 mainly outputs the driving force, whereas the MG 13 mainly receives the output of the DE 11 and generates power.

  The MG 12 mainly generates a driving force, but can also generate electric power (regenerative power generation) by using the rotation of the driving wheels 15 and can also function as a generator. At this time, a brake (regenerative brake) acts on the drive wheel 15, and the vehicle can be braked by using this together with the foot brake or the engine brake. On the other hand, the MG 13 mainly receives the output of the DE 11 and generates power, but can also function as an electric motor that receives and drives the power of the battery 19 via the inverter 18.

  The crankshaft 20 of DE11 is provided with a crank position sensor 21 that detects the piston position and the engine speed. The crank position sensor 21 is connected to the engine ECU 22 and outputs a detection result. The drive shafts 23 and 24 of the MG 12 and MG 13 are provided with rotation speed sensors 25 and 26 for detecting the respective rotation positions and rotation speeds. Each rotation speed sensor 25, 26 is connected to a motor ECU 27 and outputs a detection result.

  The power split mechanism 14 described above is constituted by a planetary gear unit. That is, the power split mechanism (planetary gear unit) 14 includes a sun gear 41, a plurality of planetary gears 42 arranged around the sun gear 41, a gear carrier 43 that holds the planetary gears 42, and a planetary gear 42 on the outer periphery. The ring gear 44 is arranged. The crankshaft 20 of the DE 11 is coupled to the gear carrier 43 via the central shaft 45, and the output of the DE 11 is input to the gear carrier 43 of the planetary gear unit 14. The MG 12 has a stator 46 and a rotor 47 inside. The rotor 47 is coupled to the ring gear 44 via the drive shaft 23, and the rotor 47 and the ring gear 44 are connected to the speed reducer 16 via a gear unit (not shown). Are combined. The speed reducer 16 transmits the output input from the MG 12 to the ring gear of the planetary gear unit 14 to the drive shaft 17, and the MG 12 is always connected to the drive shaft 17.

  Similarly to the MG 12 described above, the MG 13 has a stator 48 and a rotor 49 inside, and the rotor 49 is coupled to the sun gear 41 via the drive shaft 24 and a gear unit (not shown). That is, the output of the DE 11 is divided by the planetary gear unit 14 and input to the rotor 49 of the MG 13 via the sun gear 41. The output of the DE 11 is divided by the planetary gear unit 14 and can be transmitted to the drive shaft 17 via the ring gear 44 or the like.

  The MG 13 is provided with a lock mechanism 50 as switching means for switching the planetary gear unit 14 between an operating state and a non-operating state. This lock mechanism 50 can be operated by the motor ECU, and by stopping the rotation of the rotor 48 of the MG 13, the planetary gear unit 14 is brought into a non-operating state, that is, a locked state, and power consumption due to driving of the MG 13 can be reduced. it can. The locking mechanism may be a friction type, a claw or pin coupling type, or may be one that controls the rotational speed of the MG 13 by the inverter 18.

  Then, by controlling the amount of power generated by the MG 13 to control the rotation of the sun gear 41, the entire planetary gear unit 14 can be used as a continuously variable transmission. That is, the output of DE 11 or MG 12 is output to the drive shaft 17 after being shifted by the planetary gear unit 14. Further, the rotational speed of the DE 11 can be controlled by controlling the power generation amount of the MG 13 (power consumption when it functions as an electric motor). Note that when the rotational speeds of the MG12 and MG13 are controlled, the motor ECU 27 controls the inverter 18 with reference to the outputs of the rotational sensors 25 and 26, whereby the rotational speed of the DE11 can also be controlled. is there.

  The various controls described above are controlled by a plurality of electronic control units (ECUs). The driving by DE11 and the driving by MG12 and MG13, which are characteristic as a hybrid vehicle, are comprehensively controlled by the main ECU. That is, the distribution of the output of DE 11 and the output of MG 12 and MG 13 is determined by main ECU 28, and control commands are output to engine ECU 22 and motor ECU 27 to control DE 11, MG 12, and MG 13.

  Further, the engine ECU 22 and the motor ECU 27 also output information on the DE 11, MG 12, and MG 13 to the main ECU 28. The main ECU 28 is also connected to a battery ECU 29 that controls the battery 19 and a brake ECU 30 that controls the brake. The battery ECU 29 monitors the state of charge of the battery 19 and outputs a charge request command to the main ECU 28 when the amount of charge is insufficient. Receiving the charge request, the main ECU 28 controls the MG 13 to generate power so that the battery 19 is charged. The brake ECU 30 controls the vehicle and controls the regenerative braking by the MG 12 together with the main ECU 28.

  Since the hybrid vehicle of the present embodiment is configured as described above, by distributing the necessary output required for the entire vehicle to DE11 and MG12 (MG13) while operating the hybrid vehicle, DE11 It is possible to satisfy the output required for the entire vehicle while controlling the driving state to a desired driving state.

  That is, in the acceleration traveling of the hybrid vehicle, as shown by the solid line in FIG. 2, the main ECU 28 increases the rotational speed of the DE 11 and starts power generation by the MG 13 as a generator, and the generated power and battery of the MG 13 The MG 12 is driven by the electric power stored in 19 so as to obtain a predetermined driving force. When the hybrid vehicle is shifted from accelerated running to steady running, as shown by a two-dot chain line in FIG. 2, the vehicle can mainly run at DE11, and power generation by the MG 13 as a generator is performed to increase efficiency. Is controlled to the minimum, that is, the rotational speed is reduced to zero. At this time, it is desirable that the rotation of the rotor 48 of the MG 13 is locked and stopped by the lock mechanism 50 so that the planetary gear unit 14 is in an inoperative state (locked state) and power consumption due to driving of the MG 13 is reduced. However, if the rotation of the MG 13 is suddenly fixed, the impact is transmitted to the vehicle and drivability is reduced. In addition, depending on the traveling state of the hybrid vehicle, it may be necessary to release the lock immediately after the lock mechanism 50 locks the rotation of the MG 13, and the power consumption increases and the service life decreases due to frequent operation of the lock mechanism 50. There is a risk of inviting.

Therefore, in this embodiment, when the driving state of the hybrid vehicle is detected (driving state detecting means) and it is determined that the hybrid vehicle is in the stable running state, the motor ECU (switching means) 27 is operated by the lock mechanism 50 by the MG13. Is fixed so that the planetary gear unit (power split mechanism) 14 is switched to the non-operating state. In this case, the driving state detecting means detects a change amount per unit time of the output of the hybrid vehicle, and the motor ECU 27 sets a predetermined change amount of the output per unit time of the hybrid vehicle. When the value is less than or equal to the value, it is determined that the hybrid vehicle is in a stable running state. Specifically, the engine required output Pe _(n) and the vehicle speed Speed _(n) are used, but regardless of this, the accelerator opening, the actual rotational speed of the MG 13 and the like may be used.

  Here, the output control by the hybrid vehicle of a present Example is demonstrated based on the flowchart of FIG.

In the output control by the hybrid vehicle of this embodiment, as shown in FIG. 3, the engine request output Pe _(n) is read in step S11, and the vehicle speed Speed _(n) is read in step S12. In this case, the engine required output Pe _(n) is calculated and used based on the detection signal of the accelerator position sensor, and the vehicle speed Speed _(n) uses the detection signal of the vehicle speed sensor.

In step S13, it is determined whether or not the current vehicle speed Speed _(n) is higher than the lock permitted vehicle speed (for example, 60 km / h) of the planetary gear unit (power split mechanism) 14. Here, if the current vehicle speed Speed _(n) is equal to or lower than the planetary gear unit 14 lock permission vehicle speed, the routine exits without doing anything. On the other hand, when the current vehicle speed Speed _(n) is higher than the lock permission vehicle speed (for example, 60 km / h) of the planetary gear unit (power split mechanism) 14 in step S13, the process proceeds to step S14 and subsequent steps, and the lock mechanism 50 is locked. Execute release judgment.

That is, in step S14, a change amount ΔPe _(n) per unit time of the engine required output Pe _(n) is obtained from the following equation (1). In step S15, a change amount ΔSpeed of the vehicle speed Speed _(n) per unit time. _(n) is obtained from the following formula (2).
ΔPe _(n) = Pe _(n) −Pe _(n−1)) (1)
ΔSpeed _(n) = Speed _(n) −Speed _(n−1)) (2)

In step S16, whether the change amount ΔPe _(n) of the engine request output is lower than a preset reference change amount ΔPe _{(base) of} the engine request output, or the change amount ΔSpeed _{(n) of the} vehicle speed is set in advance. It is determined whether the vehicle speed is lower than the reference change amount ΔSpeed _(base) . If it is determined in step S16 that the engine required output change amount ΔPe _(n) is lower than the reference change amount ΔPe _(base) or the vehicle speed change amount ΔSpeed _(n) is lower than the reference change amount ΔSpeed _(base) , step In S17, the lock mechanism 50 locks the MG 13, that is, the planetary gear unit 14. On the other hand, in step S16, a change amount .DELTA.Pe of requested engine output _(n) is the reference change amount .DELTA.Pe _(base) or more and, if the vehicle speed change amount DerutaSpeed _(n) is the reference change amount ΔSpeed _(base) or more, In step S18, the lock mechanism 50 performs unlocking of the MG 13, that is, the planetary gear unit 14, and if the lock has already been released, the released state is maintained.

In this case, the reference change amount ΔPe _(base) of the engine required output increases as the engine required output Pe _(n) increases, that is, the execution condition in the non-operating state is relaxed. Further, the vehicle speed reference change amount ΔSpeed _(base) decreases as the vehicle speed Speed _(n) increases, that is, the execution condition of the non-operating state becomes severe.

As described above, in the hybrid vehicle of this embodiment, the planetary gear unit 14 as the power split mechanism transmits the output of the DE 11 to the drive wheels 15 and the MG 13 as the generator, and the output of the MG 12 as the electric motor. to allow power transmission to the drive wheels 15, also can be switched to the planetary gear unit 14 in the operating state and a non-operating state by fixing the rotation of the lock mechanism 50 MG132, the requested engine output change amount .DELTA.Pe _(n) is the reference change When the amount ΔPe _(base) is lower or the vehicle speed change amount ΔSpeed _(n) is lower than the reference change amount ΔSpeed _(base) , the lock mechanism 50 locks the MG 13 and the planetary gear unit 14 is in an inoperative state. To switch to.

  Accordingly, the planetary gear unit 14 is frequently inactivated and deactivated only when the hybrid vehicle is traveling stably without repeating acceleration and deceleration. The switching operation is eliminated, an increase in power consumption due to the operation of the lock mechanism 50 can be suppressed, and the life of the lock mechanism 50 can be extended.

  As described above, the hybrid vehicle according to the present invention prevents frequent switching by switching the power split mechanism to the non-operating state only when the hybrid vehicle is in a stable running state. It is useful when applied to a hybrid vehicle that can run using a motor as a power source.

1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention. It is a collinear diagram showing the driving force of the generator in a hybrid vehicle, an engine, and an electric motor. It is a flowchart showing the output control by the hybrid vehicle of a present Example.

Explanation of symbols

11 Diesel engine, DE
12 Motor generator, MG (electric motor)
13 Motor generator, MG (generator)
14 Power distribution mechanism (planetary gear unit)
18 Inverter 19 Battery 22 Engine ECU
27 Motor ECU
28 Main ECU
29 Battery ECU
41 Sun gear 42 Planetary gear 43 Gear carrier 44 Ring gear 50 Lock mechanism

Claims (2)

  An engine, a generator capable of generating power using at least a part of the output of the engine, an electric motor capable of rotating upon receipt of electric power supplied from the generator, and output of the engine to drive wheels and the generator A power split mechanism for transmitting power and transmitting power from the electric motor to the drive wheels, switching means for switching the power split mechanism between an operating state and a non-operating state, and a driving state detection for detecting a driving state of the hybrid vehicle And a control means for switching the power split mechanism to a non-operating state by the switching means when the driving state detecting means detects a stable running state of the hybrid vehicle. 2. The hybrid vehicle according to claim 1, wherein the control unit determines that the hybrid vehicle is in the stable running state when an output change amount of the hybrid vehicle is equal to or less than a predetermined value set in advance. A featured hybrid vehicle.

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