Hybrid vehicle

Abstract

To provide a hybrid vehicle which can restrain an engine from increasing and decreasing rotation frequency even when regeneration strength is switched in such a condition that amount of charge to a battery for driving is restricted.SOLUTION: A hybrid vehicle comprises a shift device which switches regeneration strength of kinetic energy and a throttle control device which decreases opening degree of intake throttle of an engine from predetermined opening for each regeneration strength for rotation frequency of the engine when regeneration strength is strengthened in such a condition that amount of charge for a battery for driving is restricted while increases the opening degree of the intake throttle from predetermined opening for each regeneration strength for the rotation frequency when the regeneration strength is weakened.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a hybrid vehicle.

Background Art

[0002] Patent Document 1 describes a hybrid vehicle including a control unit that performs motoring control to drive a generator with the regenerative power of a drive motor while shutting off the fuel supply to an engine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the hybrid vehicle disclosed in Patent Document 1, when the regeneration intensity is switched in a state where the charge amount to the drive battery is limited, the engine speed increases or decreases, so there is a possibility that vibration may occur in the hybrid vehicle.

[0005] In view of the above circumstances, at least one embodiment of the present invention aims to provide a hybrid vehicle capable of suppressing an increase or decrease in the engine speed even when the regeneration intensity is switched in a state where the charge amount to the drive battery is limited.

Means for Solving the Problems

[0006] (1) A hybrid vehicle according to at least one embodiment of the present invention includes an engine, a generator driven by the engine, a driving battery that charges the electricity generated by the generator, and a driving motor driven by the electricity supplied from the generator or the driving battery. In the driving motor, the electric energy regenerated from the kinetic energy is charged into the driving battery. When the charging amount to the driving battery is limited, the generator rotates the engine by the electric energy regenerated from the kinetic energy in the driving motor or the electric energy discharged from the driving battery to the generator. A hybrid vehicle comprising a shift device for switching the regeneration intensity of the kinetic energy, and a throttle control device for reducing the opening degree of the intake throttle of the engine to be less than a predetermined opening degree for each regeneration intensity with respect to the engine speed when the regeneration intensity is increased in a state where the charging amount to the driving battery is limited, and increasing the opening degree of the intake throttle to be greater than a predetermined opening degree for each regeneration intensity with respect to the engine speed when the regeneration intensity is decreased.

[0007] According to the configuration of (1) above, when the regeneration intensity is increased in a state where the charging amount of the driving battery is limited, the opening degree of the intake throttle of the engine is made smaller than the predetermined opening degree for each regeneration intensity with respect to the engine speed. Therefore, the pumping loss (mechanical loss) of the engine increases. As a result, the amount of electricity consumed by the generator increases, so that an increase in the engine speed due to an increase in the regeneration intensity can be suppressed. On the other hand, when the regeneration intensity is increased in a state where the charging amount of the driving battery is limited, the opening degree of the intake throttle of the engine is made larger than the predetermined opening degree for each regeneration intensity with respect to the engine speed. Therefore, the pumping loss of the engine decreases. As a result, the amount of electricity consumed by the generator decreases, so that a decrease in the engine speed due to a decrease in the regeneration intensity can be suppressed. Thus, even when the regeneration intensity is switched in a state where the charging amount to the driving battery is limited, an increase or decrease in the engine speed can be suppressed.

[0008] (2) In some embodiments, in the configuration of (1) above, the throttle control device restricts the opening degree of the intake throttle based on the minimum opening degree of the intake throttle predetermined with respect to the engine speed.

[0009] According to the configuration of (2) above, by setting the minimum opening degree of the intake throttle predetermined with respect to the engine speed to an opening degree at which fouling of the exhaust air-fuel ratio sensor installed in the engine exhaust passage is unlikely to occur, fouling of the exhaust air-fuel ratio sensor installed in the engine exhaust passage can be suppressed.

[0010] (3) In some embodiments, in the configuration of (1) above, the throttle control device releases the restriction by a predetermined operation of the shift device.

[0011] According to the configuration of (3) above, by releasing the restriction on the opening degree of the intake throttle, it is possible to switch to a regeneration intensity with an opening degree less than the minimum opening degree.

[0012] (4) In some embodiments, in any one of the configurations of (1) to (3) above, the shift device includes a regeneration level selector attached to the steering.

[0013] According to the configuration of (4) above, the regeneration intensity can be switched by operating the regeneration level selector while holding the steering.

Advantages of the Invention

[0014] According to at least one embodiment of the present invention, even if the regeneration intensity is switched while the charge amount to the drive battery is limited, an increase or decrease in the engine speed can be suppressed.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

[0017] [Hybrid Vehicle] The hybrid vehicle according to the embodiment is a plug-in hybrid vehicle (PHV, PHEV) that can be charged (externally charged) from an external device (for example, a rapid charger) while parked, and can supply power to the outside (for example, a general household) while parked, but is not limited thereto. The hybrid vehicle according to the embodiment is a hybrid vehicle that drives the front two wheels, but may also be a hybrid vehicle that drives four wheels.

[0018] [Configuration of Hybrid Vehicle] As shown in FIG. 1, a hybrid vehicle 1 according to an embodiment includes an engine 11, a generator 12 driven by the engine 11, a drive battery 13 that charges electricity generated by the generator 12, and a drive motor 15 that drives drive wheels 14 with electricity supplied from the generator 12 or the drive battery 13.

[0019] The engine 11, the generator 12, and the drive motor 15 are fixed to a transaxle 16. The power of the engine 11 is transmitted to the generator 12 via the transaxle 16, and the power of the drive motor 15 is transmitted to the drive wheels 14 (axle 17) via the transaxle 16. A fuel pipe 18 is connected to the engine 11, and fuel is supplied to the engine 11 through the fuel pipe 18 from a fuel tank 19 provided behind the drive battery 13 in the vehicle longitudinal direction.

[0020] As shown in FIG. 2, the generator 12 and the drive motor 15 are electrically connected to a power drive unit (PDU) 20. The power drive unit 20 incorporates a generator control unit (GCU) and a motor control unit (MCU). The generator control unit controls the generator 12 and is configured to rectify the electricity generated by the generator 12 from alternating current to direct current. The motor control unit controls the drive motor 15 and is configured to convert the electricity supplied from the drive battery 13 from alternating current to direct current.

[0021] The hybrid vehicle 1 configured as described above selects either an EV driving mode in which the engine 11 is stopped or an engine driving mode in which the engine 11 is operated. Then, the electric energy regenerated from kinetic energy in the driving motor 15 is charged to the driving battery 13 via the power drive unit 20. When the amount of charge to the driving battery 13 is limited as in the case of full charge (for example, when the SOC is 93% or more), the electric energy regenerated from kinetic energy in the driving motor 15 or the electricity discharged from the driving battery 13 to the generator 12 via the power drive unit 20 causes the generator 12 to rotate the engine 11 (in the following description, the rotation of the engine 11 by the generator 12 in this way is referred to as "motoring"). As a result, the electric energy regenerated from kinetic energy in the driving motor 15 or the electricity discharged from the driving battery 13 is consumed, and the electric energy not consumed by the generator 12 is charged to the driving battery 13.

[0022] In addition to the power drive unit 20 described above, the hybrid vehicle 1 according to the embodiment includes a battery management device (BMU) 21 that manages the driving battery 13, an engine control device (engine ECU) 22 that controls the engine 11, and a running control device (HEV-ECU) 23 that controls these.

[0023] The power drive unit 20, the battery management device 21, and the engine control device 22 are connected to the running control device 23 via a CAN (Controller Area Network) 24, and various information and various control signals are transmitted and received between them.

[0024] The battery management device 21, the engine control device 22, and the running control device 23 are each composed of a processor including an arithmetic unit, a register for storing instructions and information, and peripheral devices, a memory such as a ROM (Read Only Memory) and a RAM (Random Acess Memory), and an input interface.

[0025] A shift device 25 is connected to the travel control device 23, and a shift position selection unit (regeneration intensity selection unit) 24 is provided in the travel control device 23. The shift device 25 is composed of a selector lever 27 installed on the center console, but a paddle-type regeneration level selector 28 may be attached to the steering, although the regeneration level selector 28 is not essential.

[0026] As shown in FIG. 3, the selector lever 27 can be moved and operated from the home position to positions of R (reverse), N (neutral), D (drive), and B (regenerative brake). As shown in FIG. 5, when the selector lever is operated to D, the shift position selection unit 26 selects the basic shift position "D (B2)". Also, when the selector lever 27 is operated once to B, the shift position selection unit 26 selects a regeneration intensity "B3" that is one level stronger in regeneration intensity than "D (B2)", and when the selector lever 27 is operated once again to B, the shift position selection unit 26 selects a regeneration intensity "B5" with the maximum regeneration intensity. Further, when the regeneration intensity "B3" or "B5" is selected, if the selector lever 27 is operated to D, the shift position selection unit 26 selects the basic regeneration intensity "D (B2)".

[0027] As shown in FIG. 4, the paddle-type regeneration level selector 28 has a paddle plus lever 29 and a paddle minus lever 30, and each can be pulled and operated. As shown in FIG. 5, when the paddle plus lever 29 is operated once, the shift position selection unit 26 selects a regeneration intensity that is one level weaker in regeneration intensity, and when the paddle minus lever 30 is operated once, the shift position selection unit 26 selects a regeneration intensity that is one level stronger in regeneration intensity. Also, when the paddle plus lever 29 is pulled and held, the shift position selection unit 26 selects the basic regeneration intensity "D (B2)".

[0028] The regeneration intensity selected by the shift position selection unit 26 is transmitted from the travel control device 23 to the power drive unit 20 via the CAN 24, and the motor control unit sets the regeneration intensity of the drive motor 15. When the charge amount of the drive battery 13 is limited, the information is transmitted from the battery management device 21 to the power drive unit 20 and the engine control device 22 via the CAN 24, and the generator 12 rotates the engine 11 by the electric energy regenerated from the kinetic energy in the drive motor 15 or the electricity discharged from the drive battery 13 to the generator 12 via the power drive unit 20.

[0029] The rotational speed of the engine 11 rotated by the generator 12 increases or decreases depending on the electric energy regenerated from the kinetic energy in the drive motor 15 or the amount of electricity discharged from the drive battery 13 to the generator 12 (the amount of electricity consumed by the generator 12), that is, the electric energy regenerated from the kinetic energy in the drive motor 15. When the electric energy regenerated from the kinetic energy in the drive motor 15 increases, the amount of electricity consumed by the generator 12 increases, and the rotational speed of the engine 11 rotated by the generator 12 also increases. On the other hand, when the electric energy regenerated from the kinetic energy in the drive motor 15 decreases, the amount of electricity consumed by the generator 12 also decreases, and the rotational speed of the engine 11 rotated by the generator 12 also decreases.

[0030] Also, when the regeneration intensity of the kinetic energy is increased, the electric energy regenerated from the kinetic energy increases, and the amount of electricity consumed by the generator 12 and the rotational speed of the engine 11 rotated by the generator 12 increase. On the other hand, when the regeneration intensity of the kinetic energy is decreased, the electric energy regenerated from the kinetic energy decreases, and the amount of electricity consumed by the generator 12 and the rotational speed of the engine 11 rotated by the generator 12 decrease.

[0031] [Intake throttle opening with respect to engine speed] As shown in FIG. 6, the opening degree of the intake throttle with respect to the rotational speed of the engine 11 is determined in advance for each regeneration intensity of the kinetic energy, and the minimum opening degree of the intake throttle with respect to the rotational speed of the engine 11 is also determined in advance. The minimum opening degree of the intake throttle is an opening degree (LAFS fouling minimum opening degree) at which fouling of the exhaust air-fuel ratio sensor (LAFS) installed in the exhaust passage of the engine 11 is unlikely to occur, and is obtained in advance by experiments or the like. In the example shown in FIG. 6, since the intake throttle opening degree at B5 when the regeneration intensity is maximum is below the LAFS fouling minimum opening degree, the selection of the regeneration intensity "B5" is not possible. The rotational speed of the engine 11 at which the same discharge amount is obtained varies depending on the regeneration intensity of the kinetic energy. When the regeneration intensity of the kinetic energy is increased (for example, B2 → B3), the rotational speed of the engine 11 at which the same discharge amount is obtained decreases, and when the regeneration intensity is decreased (for example, B3 → B2), the rotational speed of the engine 11 at which the same discharge amount is obtained increases.

[0032] [Throttle control device] As shown in FIG. 2, the traveling control device (throttle control device) 23 according to the embodiment is provided with a throttle opening degree storage unit 31, a throttle opening degree specifying unit 32, and a throttle opening degree control unit 33. The throttle opening degree storage unit 31 stores the opening degree of the intake throttle determined in advance for each regeneration intensity with respect to the rotational speed of the engine 11, and the minimum opening degree determined in advance with respect to the rotational speed of the engine 11, but the minimum opening degree determined in advance with respect to the rotational speed of the engine 11 is not essential. The throttle opening degree specifying unit 32 refers to the throttle opening degree storage unit 31 and specifies the opening degree of the intake throttle determined in advance based on the rotational speed of the engine 11 before the regeneration intensity change and the regeneration intensity after the regeneration intensity change. The throttle opening degree control unit 33 decreases the opening degree of the intake throttle below the predetermined opening degree when the regeneration intensity of the kinetic energy is increased, while increasing the opening degree of the intake throttle above the predetermined opening degree when the regeneration intensity of the kinetic energy is decreased. That opening degree is transmitted from the traveling control device 23 to the engine control device 22, and the opening degree of the intake throttle is adjusted in the engine control device 22.

[0033] The opening degree of the intake throttle is restricted based on a predetermined minimum opening degree with respect to the rotational speed of the engine 11, but the restriction is not essential. The restriction is released by a predetermined operation of the shift device 25 (selector lever 27 or regeneration level selector 28), but the release is not essential. When the opening degree and the minimum opening degree of the intake throttle stored in the throttle opening degree storage unit 31 are the same as those shown in FIG. 6, the selection of the regeneration intensity "B5" is not possible due to the restriction of the minimum opening degree. However, the restriction of the minimum opening degree is released by a predetermined operation of the shift device 25, and the selection of the regeneration intensity "B5" becomes possible. The predetermined operation is, for example, a long-pulling operation of the paddle minus lever 30. When the paddle minus lever 30 is long-pulled, the restriction of the minimum opening degree is released, and the selection of the regeneration intensity "B5" becomes possible.

[0034] [Operation of Hybrid Vehicle] As shown in FIG. 7, in the hybrid vehicle 1 according to the embodiment, it is determined whether or not the charge amount of the drive battery 13 is restricted (step S11). When the charge amount of the drive battery 13 is not restricted (step S11: No), the electric energy regenerated from the kinetic energy in the drive motor 15 is charged to the drive battery 13. On the other hand, when the charge amount of the drive battery 13 is restricted (step S11: Yes), the generator 12 rotates the engine 11 (motoring) by the electric energy regenerated from the kinetic energy in the drive motor 15 or the electricity discharged from the drive battery 13 to the generator 12. Thereby, the electric energy regenerated from the kinetic energy in the drive motor 15 or the electricity discharged from the drive battery 13 is consumed, and the electric energy not consumed by the generator 12 is charged to the drive battery 13.

[0035] When the shift device 25 is operated during motoring and a new regeneration intensity is selected in the shift position selection unit 26 (when the regeneration intensity is changed) (step S12: Yes), it is determined whether or not the regeneration intensity is increased in the shift position selection unit 26 (step S13).

[0036] When it is determined that the regeneration intensity has been increased (step S13: Yes), the throttle opening degree specifying unit 32 refers to the throttle opening degree storage unit 31 and specifies the opening degree of the intake throttle (predetermined opening degree) based on the engine speed before the increase and the regeneration intensity after the increase (step S14). When the opening degree of the intake throttle is specified, the throttle opening degree control unit 33 decreases the opening degree of the intake throttle below the specified opening degree of the throttle (predetermined opening degree). Then, the opening degree is transmitted from the travel control device 23 to the engine control device 22, and the engine control device 22 decreases the opening degree of the intake throttle (step S15). As a result, the pumping loss (mechanical loss) of the engine 11 increases, and the amount of electricity consumed by the generator 12 increases, so that an increase in the engine speed of the engine 11 due to increasing the regeneration intensity can be suppressed.

[0037] Note that the opening degree of the intake throttle is limited based on a predetermined minimum opening degree with respect to the engine speed of the engine 11, but the limitation is released by a predetermined operation of the shift device 25 (selector lever 27 or regeneration level selector 28).

[0038] On the other hand, when it is determined that the regeneration intensity has been decreased (step S13: No), the throttle opening degree specifying unit 32 refers to the throttle opening degree storage unit 31 and specifies the opening degree of the intake throttle (predetermined opening degree) based on the engine speed of the engine 11 before the decrease and the regeneration intensity after the decrease (step S16). When the opening degree of the intake throttle is specified, the throttle opening degree control unit 33 increases the opening degree of the intake throttle above the specified opening degree of the throttle (predetermined opening degree). Then, the opening degree is transmitted from the travel control device 23 to the engine control device 22, and the engine control device 22 increases the opening degree of the intake throttle (step S17). As a result, the pumping loss (mechanical loss) of the engine 11 decreases, and the amount of electricity consumed by the generator 12 decreases, so that a decrease in the engine speed of the engine 11 due to decreasing the regeneration intensity can be suppressed.

[0039] [Effect of Hybrid Vehicle] According to the hybrid vehicle 1 according to the embodiment, when the regeneration intensity is increased while the charge amount of the drive battery 13 is limited, the opening degree of the intake throttle of the engine 11 is made smaller than the predetermined opening degree for each regeneration intensity with respect to the rotational speed of the engine 11. Therefore, the pumping loss (mechanical loss) of the engine 11 increases. As a result, since the amount of electricity consumed by the generator 12 increases, an increase in the rotational speed of the engine 11 due to an increase in the regeneration intensity can be suppressed. On the other hand, when the regeneration intensity is increased while the charge amount of the drive battery 13 is limited, the opening degree of the intake throttle of the engine 11 is made larger than the predetermined opening degree for each regeneration intensity with respect to the rotational speed of the engine 11. Therefore, the pumping loss of the engine 11 decreases. As a result, since the amount of electricity consumed by the generator 12 decreases, a decrease in the rotational speed of the engine 11 due to a decrease in the regeneration intensity can be suppressed. Thereby, even if the regeneration intensity is switched while the charge amount to the drive battery 13 is limited, an increase or decrease in the rotational speed of the engine 11 can be suppressed.

[0040] Further, by setting the minimum opening degree of the intake throttle predetermined with respect to the rotational speed of the engine 11 to an opening degree at which fouling of the exhaust air-fuel ratio sensor installed in the exhaust passage of the engine 11 is unlikely to occur, fouling of the exhaust air-fuel ratio sensor installed in the exhaust passage of the engine 11 can be suppressed.

[0041] Also, by canceling the restriction on the opening degree of the intake throttle by a predetermined operation of the shift device 25, it is possible to switch to a regeneration intensity with an opening degree less than the minimum opening degree.

[0042] The present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

Explanation of Reference Numerals

[0043] 1 Hybrid vehicle 11 Engine 12 Generator 13 Driving battery 14 Driving wheel 15 Driving motor 16 Transaxle 17 Axle 18 Fuel pipe 19 Fuel tank 20 Power drive unit (PDU) 21 Battery management unit (BMU) 22 Engine control unit (engine ECU) 23 Driving control unit / throttle control unit (HEV-ECU) 24 CAN 25 Shift device 26 Shift position selection unit (regeneration intensity selection unit) 27 Level selector 28 Regeneration level selector 29 Paddle plus lever 30 Paddle minus lever 31 Throttle opening memory unit 32 Throttle opening identification unit 33 Throttle opening control unit

Claims

1. An engine, a generator driven by the engine, a driving battery that charges the electricity generated by the generator, a driving motor driven by the electricity supplied from the generator or the driving battery, comprising: In the driving motor, the electric energy regenerated from kinetic energy is charged to the driving battery. When the charging amount to the driving battery is limited, the electric energy regenerated from kinetic energy in the driving motor, or the electric energy discharged from the driving battery to the generator, causes the generator to rotate the engine. A hybrid vehicle, a shift device for switching the regeneration intensity of the kinetic energy, In a state where the charging amount to the driving battery is limited, when the regeneration intensity is increased, the opening degree of the intake throttle of the engine is reduced to be smaller than a predetermined opening degree for each regeneration intensity with respect to the engine speed. On the other hand, when the regeneration intensity is decreased, the opening degree of the intake throttle is increased to be larger than a predetermined opening degree for each regeneration intensity with respect to the engine speed. A throttle control device, A hybrid vehicle comprising the above.

2. The throttle control device limits the opening degree of the intake throttle based on a predetermined minimum opening degree of the intake throttle with respect to the engine speed. The hybrid vehicle according to claim 1.

3. The throttle control device releases the limitation by a predetermined operation of the shift device. The hybrid vehicle according to claim 2.

4. A paddle-type regeneration level selector is attached to the steering. The hybrid vehicle according to any one of claims 1 to 3.

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