JP2023096711A - hybrid vehicle - Google Patents

Abstract

To provide a hybrid vehicle that can appropriately achieve deceleration, while making both improvement in NV performance and suppression of overheat of a motor compatible.SOLUTION: A hybrid vehicle is equipped with: a first motor that can receive power of an engine to generate electric power; a power distributing mechanism that can output power of the engine to a wheel and input all or portion of power of the engine to the first motor; a second motor that can receive supply of electric power from a power storage device to output power for travelling and functions as a power generator during regenerative braking; and a clutch provided between the engine and the first motor, which when the vehicle cannot achieve target deceleration due to input/output restriction on a battery, disengages the clutch and then executes regenerative auxiliary control by which the first motor is subjected to power-running using electric power generated by the second motor, and when a temperature of the first motor is higher than a first predetermined value, sets an upper limit output value to a smaller value, during the regenerative auxiliary control.SELECTED DRAWING: Figure 3

Description

The present invention relates to hybrid vehicles.

Conventionally, an engine that outputs power using gasoline or light oil as fuel, a traction motor that receives power from a power storage device and outputs power, and a power generator that receives all or part of the power of the engine and generates power Hybrid vehicles equipped with motors are becoming popular.

In such a hybrid vehicle, the power transmission systems of the engine, the generator motor, and the drive motor are connected via a power distribution integration mechanism composed of, for example, a planetary gear mechanism. Fuel efficiency is improved by appropriately switching between motor driving (hereinafter also referred to as BEV driving), an engine driving mode in which the vehicle is driven only by the power from the engine, and a hybrid driving mode in which the vehicle is driven by power from both the engine and the driving motor. We are trying to

Regarding the hybrid vehicle as described above, Patent Literature 1 discloses a technique for powering MG1 using power generated by motor MG2 when charging of the battery is limited during regenerative braking of MG2.

JP 2010-58579

Although deceleration of the hybrid vehicle can be obtained with the above technique, depending on the required deceleration, the motor may be over-rotated and the motor may heat up.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid vehicle capable of suitably decelerating while suppressing overheating of the motor.

an engine capable of outputting power,
a first motor capable of generating power by receiving the power of the engine; and a power distribution mechanism capable of outputting the power of the engine to the wheels as driving power and inputting all or part of the power of the engine to the first motor. ,
a second motor that can output power for running by receiving electric power supply from a power storage device and that functions as a generator during regenerative braking; and a control unit that controls each operation of the engine, the first motor, and the second motor. A hybrid vehicle comprising
further comprising a clutch provided between the first motor and the wheel,
When the vehicle cannot output the target deceleration due to input/output restrictions of the battery, the control unit executes regeneration assist control for powering the first motor by using the power generated by the second motor after disengaging the clutch. and, during the regeneration assist control, when the temperature of the first motor is higher than a first predetermined value, the upper limit output value is set smaller than when the temperature is lower than the first predetermined value. Hybrid vehicle .
hybrid vehicle.

According to the hybrid vehicle of the present invention, when the second motor is regeneratively braked, even if the charging of the power storage device is limited, the power generated by the second motor is used to power-run the first motor. When the temperature is higher than the first predetermined value, the upper limit output value can be set smaller than when the temperature is lower than the first predetermined value. As a result, the number of rotations of the first motor can be suppressed, so that deceleration can be favorably obtained while suppressing heat generation of the first motor.

1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment; FIG. FIG. 2 is a diagram showing a brake device in the hybrid vehicle of FIG. 1; FIG. 4 is a flowchart showing a control procedure executed by a hybrid ECU;

The hybrid vehicle of the present invention will be described in detail below.

FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle 10 that is a first embodiment of the invention. In FIG. 1, a power transmission system is indicated by a solid line, a power line is indicated by a dashed line, and a signal line is indicated by a broken line. The hybrid vehicle 10 includes an engine 12 capable of outputting driving power, two three-phase AC synchronous motor generators (hereinafter simply referred to as "motors") MG1 (first motor) and MG2 (second motor), and power and a distribution integration mechanism 14 .

The engine 12 is an internal combustion engine that uses gasoline, light oil, or the like as fuel. The engine 12 is electrically connected to an engine ECU (Electronic Control Unit) (hereinafter referred to as "engine ECU") 16, and receives control signals from the engine ECU 16 for fuel injection, ignition, intake air amount, intake air The opening and closing of valves and exhaust valves are controlled.

The power distribution mechanism 14 includes a sun gear 18 arranged in the center, a ring gear 20 arranged concentrically with the sun gear and having internal teeth on the inner periphery of an annular ring, and a plurality of carriers 22 meshing with both the sun gear 18 and the ring gear 20. and a planetary gear mechanism. A plurality of carriers 22 are each rotatably mounted at the end of carrier support member 26 .

In the power distribution mechanism 14, a carrier shaft 28 connected to a carrier support member 26 is connected to the output shaft 13 of the engine 12 via a damper 24 for damping torque impact, and a sun gear 18 is connected to a rotor 29 of a motor MG1. The rotating shaft 30 connected to the engine is connected via a clutch mechanism 72 , and the ring gear 20 is connected to a speed reducer 34 via a ring gear shaft 32 .

The clutch mechanism 72 is provided in a power transmission system between the engine 12 and the motor MG1, and may be of a known construction such as a disc clutch, fluid clutch, dog clutch, or the like. When the clutch mechanism 72 is connected (hereinafter also referred to as ON), the engine 12 and the motor MG1 are connected via the sun gear 18, the carrier 22 and the like, and the clutch mechanism 72 is disconnected (hereinafter also referred to as OFF). , the engine 12 and the motor MG1 are disconnected.

Under the condition that the clutch mechanism 72 is turned on, in the power distribution mechanism 14, when the motor MG1 functions as a generator, power from the engine 12 input to the carrier 22 via the carrier shaft 28 is supplied to the sun gear 18 side. and the ring gear 20 according to the gear ratio thereof, and when the motor MG1 functions as an electric motor, the power of the engine 12 input to the carrier 22 via the carrier shaft 28 and the power from MG1 input from the sun gear 18 are integrated and input from the ring gear 20 through the ring gear shaft 32 to a speed reducer 34 including a gear train having a predetermined speed reduction ratio.

A rotary shaft 38 connected to the rotor 36 of the motor MG2 is also connected to the speed reducer 34, and power from the motor MG2 is input to the speed reducer 34 when the motor MG2 functions as an electric motor.

Power input from at least one of the ring gear shaft 32 and the rotating shaft 38 of the motor MG2 is transmitted to the axle 40 via the speed reducer 34, thereby driving the wheels 42 to rotate.
On the other hand, when power is input from wheels 42 and axle 40 to rotary shaft 38 via speed reducer 34 during regenerative braking, motor MG2 functions as a generator. Here, regenerative braking is not limited to when the driver applies the brakes to decelerate the vehicle. This includes cases such as when the vehicle is running due to the action of gravity.

Motors MG1 and MG2 are electrically connected to corresponding inverters 44 and 46, respectively. 50 is electrically connected. A secondary battery such as a nickel-metal hydride battery or a lithium-ion battery is preferably used as the battery 50 .
Also, instead of the battery, a capacitor that does not involve a chemical reaction may be used as the power storage device.

When the motors MG1 and MG2 function as electric motors, the DC voltage Vb supplied from the battery 50 through the smoothing capacitor 52 is stepped up to the output voltage Vc by the converter 48 and then supplied to the inverters 44 and 46 through the smoothing capacitor 54. input (converter output voltage V
c corresponds to the inverter input voltage and system voltage VH (the same applies hereinafter), is converted into an AC voltage by inverters 44 and 46, and is input to motors MG1 and MG2.

Conversely, when the motors MG1 and MG2 function as power generators, the generated power output from the motors MG1 and MG2 is the inverter 4 provided that the charging of the battery 50 is not limited.
4 and 46, the AC voltage is converted into a DC voltage, and then the voltage is stepped down by the converter 48 to be supplied to the battery 5.
charged to 0. Inverters 44 , 46 share power line 56 and ground line 58 connected to converter 48 . can be supplied to the motor to rotate or power.

Further, the motor MG1 can continuously change the engine speed by adjusting the AC voltage applied to the motor MG1 and controlling the torque. Rotation beyond the number of revolutions is suppressed.

The inverters 44 and 46 are electrically connected to a motor ECU (hereinafter referred to as a motor ECU) 60, respectively. The motors MG1 and MG2 are controlled to operate based on control signals transmitted from the motor ECU 60 . Further, the motors MG1 and MG2 are provided with rotation angle sensors 31 and 37 for detecting rotation angles of the rotors 29 and 36, respectively. Detected values by the rotation angle sensors 31 and 37 are input to the motor ECU 60 to determine the motor rotation speeds Nm1,
Used to calculate Nm2.

The battery 50 is provided with a current sensor 62 for detecting the state of charge or remaining capacity (SOC: State Of Charge). A value detected by the current sensor 62 is sent to the battery ECU
(hereinafter referred to as "battery ECU") 64. Further, the battery ECU 64 receives input of a battery voltage Vb detected by a voltage sensor (not shown), a battery temperature detected by a temperature sensor (not shown), and the like. The battery ECU 64 monitors the remaining battery charge SOC so that it is maintained within an appropriate range based on the integrated value of the charge/discharge current detected by the current sensor 62. In the vicinity, signals for output limitation and charging request are output to the hybrid ECU, which will be described later.

The engine ECU 16, the motor ECU 60, and the battery ECU 64 are electrically connected to a hybrid ECU (hereinafter referred to as a hybrid ECU) 66. As shown in FIG. The hybrid ECU 66 includes a CPU that executes control programs, a ROM that stores control programs, and the like.
, a RAM, etc. for storing various detection values in a readable and rewritable manner at any time. The hybrid ECU 66 has a function of comprehensively controlling the operation of the engine 12 and the motors MG1 and MG2 and managing the battery 50 .

The hybrid ECU 66 transmits an engine control signal to the engine ECU 16 as necessary, and transmits data (for example, engine speed N
e, etc.). In addition, the hybrid ECU 66 transmits a required torque command Tr* to the motor ECU 60 as necessary, and data (
For example, motor rotation speeds Nm1 and Nm2, motor current, etc.) are received. Further, hybrid ECU 66 receives data necessary for battery management such as remaining battery charge SOC, battery voltage, battery temperature, charge limit signal, and output limit signal from battery ECU 64 .

A vehicle speed sensor 68 and an accelerator opening sensor 70 are electrically connected to the hybrid ECU 66, and the vehicle speed Sv, which is the running speed of the hybrid vehicle 10, and the accelerator opening corresponding to the amount of depression of an accelerator pedal (not shown) are detected. Ac are input respectively.

Further, as shown in FIG. 2 , the hybrid vehicle 10 is provided with a mechanical brake device 74 for each wheel 42 for braking the wheel 42 to decelerate or stop the vehicle 10 . A hydraulic disk brake, for example, is preferably used for the brake device 74, but any known mechanical brake mechanism may be used. The brake device 74 is controlled in operation by a brake ECU (hereinafter referred to as a brake ECU) 76 . The brake ECU 76 is electrically connected to the hybrid ECU.

The hybrid ECU 66 is electrically connected to a brake sensor 78 that detects the depression amount or depression force of a foot brake (not shown) operated by the driver. The hybrid ECU 66 receives the detected value Bk from the brake sensor 78 and transmits a command to the brake ECU 76 so that the braking device 74 generates the required braking force. In addition, the hybrid ECU 66 can also transmit a command to the brake ECU 76 to compensate for the insufficient braking force due to the restriction of the regenerative braking of the motor MG2, as will be described later.

Next, operations of the engine 12 and the motors MG1 and MG2 in the hybrid vehicle 10 configured as described above will be schematically described. Here, the condition is that the clutch mechanism 72 is turned on and the engine 12 and the motor MG1 are in a connected state.

For example, when the hybrid vehicle 10 is started, the engine 12 is started using the motor MG1 as a so-called self-motor. When the engine is started, motor MG1 is driven by electric power supplied from battery 50 via converter 48 and inverter 44 . However, if the vehicle is started only by the power output from the motor MG2 when the vehicle is subsequently started, the engine start here is only for warm-up operation.

When the hybrid vehicle 10 is started from a stopped state, the electric power is normally supplied from the battery 50 to the motor MG2 via the converter 48 and the inverter 46 to drive the motor MG2, and the power is output only from the motor MG2 to start (motor running mode). ). However, at this time, when the remaining capacity SOC of the battery 50 is low and there is a charging request from the battery ECU 64, the engine 12 outputs and generates power, and the battery 50 is charged with the generated power.

For example, when the hybrid vehicle 10 is traveling at a relatively light load, such as when the hybrid vehicle 10 is traveling at a low speed or descending a slope, if power is output from the engine 12 which is relatively inefficient in the low-to-medium speed range, the fuel consumption is reduced. Since the engine 12 is stopped, while the remaining capacity SOC of the battery 50 is being monitored, the vehicle runs only with the power from the motor MG2 (motor running mode). At this time, when the remaining battery charge SOC decreases, the engine 12 is appropriately intermittently operated in response to a charging request from the battery ECU 64, and the engine power is used to generate electricity by the motor MG1 to charge the battery 50.

For example, during normal running in which the hybrid vehicle 10 is running at a substantially constant and stable speed, the hybrid vehicle 10 runs by outputting power from the engine 12, which has relatively good efficiency in the medium to high speed range (engine running mode). At this time, if necessary, for example, when the accelerator is temporarily stepped on strongly to accelerate rapidly, power is supplied from the motor MG1 or the battery 50, which is in a power generation state by receiving the distribution of the engine power, and the motor MG2 is supplied with power. Power is also output from the engine 12 to assist the power of the engine 12 (hybrid running mode). When the remaining battery capacity SOC is low, the output of the engine 12 is increased to increase the power distributed to the motor MG1, and the battery 50 is charged with part of the electric power generated by the motor MG1.

For example, during regenerative braking in which the hybrid vehicle 10 is decelerated by braking, power is input from the wheels 42 to the rotating shaft 38 via the wheels 40 and the speed reducer 34, and the motor MG2 functions as a generator. During regenerative braking, a braking force due to rotational resistance of the motor MG2 acts on the hybrid vehicle 10, and the regenerative electric power generated by the motor MG2 is converted into a DC voltage by the inverter 46 and stepped down by the converter 48, and then charging is limited. The battery 50 not in use is charged.

Next, the operation of hybrid vehicle 10 will be described with reference to FIG. FIG. 3 is a flow chart showing an example of the operation flow of the hybrid vehicle 10. As shown in FIG.

First, the hybrid ECU 66 determines the deceleration of the hybrid vehicle 10 from the accelerator opening sensor 70 and the brake sensor 78 (step S100). For example, the deceleration determination determines whether the hybrid vehicle 10 is decelerating due to the driver's foot brake operation or accelerator release.

After the deceleration determination is made, the hybrid ECU 66 calculates the chargeable capacity (hereinafter referred to as Win) of the battery 50 based on the information from the battery ECU 64 (step S101). The chargeable capacity of the battery is, for example, 8 KW.

After step S101, the hybrid ECU 66 calculates the target deceleration of the hybrid vehicle 10 from the vehicle speed sensor 68, the brake sensor 78, and the road surface gradient sensor 80 (step S102). A target deceleration is, for example, 0.5 m/s2. If the hybrid vehicle 10 does not reach the target deceleration as a result of step S102, the regenerative torque of the MG2 required for the target deceleration is calculated (step S103). The regenerative torque of the MG2 is calculated by, for example, vehicle weight x deceleration x tire radius/gear ratio - engine friction.

Then, the power consumption necessary for inputting the calculated regenerative torque of MG2 is calculated (step S104). Power consumption is calculated by, for example, MG2 torque*vehicle speed/3.6/tire radius*gear ratio-Win.

After step S104, the MG1 output for ensuring power consumption is calculated (step S105). After that, the clutch 72 is released (step S106). By disengaging the clutch 72, the power from the MG1 input from the sun gear 18 can be prevented from being input from the ring gear 20 to the speed reducer 34 via the ring gear shaft 32 and transmitted to the wheels 44, 46.

After step S106, the hybrid ECU 66 calculates the output upper limit value of MG1 (step S107), and when the output upper limit value of MG1 is reached, restricts the output of MG1 (step S108). The output upper limit value is calculated from the first motor temperature. Specifically, when the temperature of the first motor is higher than the first predetermined value, the upper limit output value is set smaller than when the temperature is lower than the first predetermined value. In this embodiment, the first predetermined value is 140°C. The upper limit value of the regenerative torque of MG2 is determined by the upper limit value of MG1, and the mechanical braking device 74 can compensate for the deceleration that MG1 cannot compensate for with the upper limit regenerative amount. Compensation of the braking force in this manner may be automatically executed by transmission of a command from the hybrid ECU 66 to the brake ECU 76, or may be entrusted to the brake operation by the driver who senses insufficient braking force.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments.

10 hybrid vehicle, 11 rotation position sensor, 12 engine, 13 output shaft, 14 power distribution mechanism, 16 engine ECU, 18 sun gear, 20 ring gear, 22 carrier, 24 damper, 26 carrier support member, 28 carrier shaft, 29 rotor, 30 Rotating shaft, 31 Rotation angle sensor, 38 Rotating shaft, 40 Axle, 42 Wheel, 44,46 Inverter, 48 Converter, 50 Battery, 52,54 Capacitor, 56 Power line, 58 Ground line, 60 Motor ECU, 62 Current sensor, 64 battery ECU, 66 hybrid ECU, 68 vehicle speed sensor, 70 accelerator opening sensor, 72 clutch mechanism, 74 brake device, 76 brake ECU, 78 brake sensor, MG1, MG2 motors, 80 noise sensor

Claims (1)

an engine capable of outputting power,
a first motor capable of generating power by receiving the power of the engine; and a power distribution mechanism capable of outputting the power of the engine to the wheels as driving power and inputting all or part of the power of the engine to the first motor. ,
a second motor that can output power for running by receiving electric power supply from a power storage device and that functions as a generator during regenerative braking; and a control unit that controls each operation of the engine, the first motor, and the second motor. A hybrid vehicle comprising
further comprising a clutch that connects or disconnects the first motor and the wheel;
When the vehicle cannot output the target deceleration due to input/output restrictions of the battery, the control unit executes regeneration assist control for powering the first motor by using the power generated by the second motor after disengaging the clutch. and, during the regeneration assist control, when the temperature of the first motor is higher than a first predetermined value, the upper limit output value is set smaller than when the temperature is lower than the first predetermined value. Hybrid vehicle .

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