JP2021172110A - Hybrid vehicle drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start or stop an engine while performing resonance suppression control without impairing controllability of a driving force even while the vehicle is running. SOLUTION: When an engine 22 is started or stopped while a vehicle is running, the entire required driving force is output by an e-Axle unit 18, and the engine 22 is disconnected from the automatic transmission 20 by a second clutch C2. Since the engine 22 is started and stopped while the resonance suppression control is performed by the first rotary machine MG1, the resonance suppression control can be appropriately performed by using the first rotary machine MG1 without impairing the controllability of the driving force. [Selection diagram] Fig. 1

Description

The present invention relates to a drive device of a hybrid vehicle, and more particularly to control when starting or stopping an engine while the vehicle is running.

An automatic transmission, a rotating machine provided on the upstream side of the automatic transmission, and an engine provided on the upstream side of the rotating machine are provided, and the engine and the rotating machine are used as a driving force source for traveling. A drive device for a hybrid vehicle that drives one of the front and rear wheels via the automatic transmission has been proposed. The device described in Patent Document 1 is an example thereof. In Patent Document 1, when the engine is started, resonance suppression control is performed by outputting resonance suppression motor torque by the rotating machine to suppress resonance.

Japanese Unexamined Patent Publication No. 2015-20588

However, since the engine is started while performing resonance suppression control using a rotating machine used as a driving force source for driving, the engine is operated while the vehicle is running in order to reduce the usage time of the engine, for example, to improve fuel efficiency. When trying to stop or start, there is a possibility that the driving force cannot be appropriately controlled, for example, the driving force fluctuates due to the rotating machine being used for resonance suppression control. Resonance may occur even when the engine is stopped, and it is conceivable to perform resonance suppression control using a rotating machine in the same way as when starting, but if you try to perform it while the vehicle is running, the same problem will occur. Occurs.

The present invention has been made against the background of the above circumstances, and an object of the present invention is that the engine can be started or stopped while performing resonance suppression control without impairing the controllability of the driving force even while the vehicle is running. To do so.

In order to achieve such an object, the present invention has (a) an automatic transmission, a first rotating machine provided on the upstream side of the automatic transmission, and a disconnection device on the upstream side of the first rotating machine. A hybrid drive unit comprising an engine detachably connected via the engine and the engine and the first rotating machine as a driving force source for traveling to drive one of the front and rear wheels via the automatic transmission. (b) A driving device for a hybrid vehicle including a second rotating machine, and the second rotating machine is used as a driving force source for traveling to drive the other of the front and rear wheels. , (C) When the engine is started or stopped while the vehicle is running, the entire required driving force is output by the electric drive unit, power transmission via the automatic transmission is cut off, and the disconnection device is used. It is characterized by having a hybrid control device for starting or stopping the engine while performing resonance suppression control by the first rotating machine in a state where the engine and the first rotating machine are connected to each other.

In such a hybrid vehicle drive device, when the engine is started or stopped while the vehicle is running, the entire required driving force is output by the electric drive unit, and the first rotating machine is separated from the power transmission path. Since the engine is started or stopped while the resonance suppression control is performed, the resonance suppression control can be appropriately performed by using the first rotating machine without impairing the controllability of the driving force.

It is a schematic block diagram of the drive device of the hybrid vehicle which is one Example of this invention, and is also the figure which showed the main part of the control system together. It is a flowchart explaining the operation at the time of starting an engine by the engine start stop control part of FIG. It is an example of a time chart for explaining the change in torque of each part and the change in the operating state of the clutch when the engine is started according to the flowchart of FIG. It is a flowchart explaining the operation when the engine is stopped by the engine start stop control part of FIG. It is an example of a time chart for explaining the change in torque of each part and the change in the operating state of the clutch when the engine is stopped according to the flowchart of FIG.

The engine used as a driving force source for traveling is an internal combustion engine that generates power by burning fuel such as a gasoline engine or a diesel engine. Both the first rotating machine and the second rotating machine are used as a driving force source for traveling, and may be an electric motor or a motor generator that can be selectively used as an electric motor and a generator. The electric drive unit may be, for example, one in which the output of a single second rotating machine is distributed to the left and right by a differential device to rotate the left and right wheels, but a pair of second units are used to drive the left and right wheels separately. It may be configured to include a rotating machine. The automatic transmission provided in the hybrid drive unit is, for example, a stepped transmission such as a planetary gear type or a constantly meshing parallel two-axis type, or a continuously variable transmission such as a belt type. It is arranged in the power transmission path between. The disconnection device between the first rotary machine and the engine is, for example, a friction engagement type clutch or brake, or a meshing type clutch. To cut off the power transmission via the automatic transmission, in addition to the case where the automatic transmission itself can form a neutral state that cuts off the power transmission, a second disconnection device is provided between the first rotating machine and the automatic transmission. May be done. That is, a first connecting / disconnecting device is provided between the engine and the first rotating machine, and a second connecting / disconnecting device is provided between the first rotating machine and the automatic transmission. With the first rotating machine and the automatic transmission separated and the engine and the first rotating machine connected by the first connecting / disconnecting device, the engine is started or started while the first rotating machine performs resonance suppression control. Just stop.

A hybrid control device that starts or stops an engine while performing resonance suppression control by a first rotating machine is, for example, an engine start / stop that automatically starts or stops an engine according to an engine start request and a stop request while the vehicle is running. It is configured to be functionally equipped with a control unit. The engine start / stop control unit may perform resonance suppression control by the first rotating machine in a state where power transmission via the automatic transmission is cut off both when the engine is started and when the engine is stopped. Resonance suppression control by the first rotating machine may be performed only at either the time or the stop time. When the engine is started or stopped without the resonance suppression control by the first rotating machine, the engine may be started or stopped, for example, in a state where power transmission is performed via an automatic transmission. The hybrid control device functionally has a driving mode switching control unit that switches a plurality of driving modes automatically according to a driving state such as a required driving force or a vehicle speed or according to a driver's mode switching operation, and starts and stops the engine. The control unit is configured to start and stop the engine according to the engine start request and the engine stop request accompanying the switching of the traveling mode. The running mode includes at least an engine running mode in which the engine is used as a driving force source for running, and a running mode in which the engine is stopped and the first rotating machine and / or the second rotating machine is used as a driving force source for running. A plurality of driving modes, such as an EV driving mode, in which at least the necessity of the engine is different are defined.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a drive device 10 (hereinafter, simply referred to as a drive device 10) of a hybrid vehicle to which the present invention is applied, and includes main parts of a control system for various controls in the drive device 10. It is a figure shown by. The drive device 10 includes a 1M-HV (1 motor hybrid) unit 14 that rotationally drives the left and right front wheels 12, and an e-Axle unit 18 that rotationally drives the left and right rear wheels 16. It is a wheel drive type drive device. The 1M-HV unit 14 includes an automatic transmission 20 capable of establishing a plurality of gear stages having different gear ratios by a plurality of hydraulic transmission engaging devices, and a hydraulic type on the upstream side of the automatic transmission 20. The first rotary machine MG1 detachably connected via the second clutch C2 and the engine 22 detachably connected via the hydraulic first clutch C1 to the upstream side of the first rotary machine MG1. The engine 22 and the first rotary machine MG1 are used as a driving force source for traveling. Then, the driving force transmitted from at least one of the engine 22 and the first rotary machine MG1 to the automatic transmission 20 is distributed to the left and right drive shafts 26 by the differential device 24, and is transmitted from the drive shafts 26 to the left and right front wheels 12. Will be done. The 1M-HV unit 14 corresponds to a hybrid drive unit that drives one of the front and rear wheels.

The engine 22 is an internal combustion engine such as a gasoline engine or a diesel engine, and its operating state such as engine torque is controlled according to an engine control command signal Se output from an HV-ECU (Electronic Control Unit) 70. The engine 22 is connected to the first clutch C1 via a damper device (not shown) without using a fluid coupling such as a torque converter. The first rotary machine MG1 is a motor generator that can be selectively used as an electric motor and a generator, and is connected to a high voltage battery 86 via a PCU (Power Control Unit) 82 equipped with an inverter or the like and a DC-DC converter 84. By controlling the PCU82 according to the MG1 control command signal Smg1 output from the HV-ECU 70, the PCU82 can function as an electric motor or a generator and the torque is controlled.

The first clutch C1 and the second clutch C2 are both single-plate or multi-plate friction clutches, and are controlled to be disengaged by hydraulic oil supplied from a hydraulic control circuit including a valve body 28. The first clutch C1 corresponds to the first engagement / disconnection device, and the second clutch C2 corresponds to the second engagement / disconnection device. The valve body 28 is provided with a plurality of solenoid valves 30 for disengagement control of the clutches C1 and C2 for disconnection and engagement and engagement / disengagement control of the speed change engagement device of the automatic transmission 20. By controlling the solenoid valve 30 such as the above according to the hydraulic control command signal Sat output from the HV-ECU 70, the clutches C1 and C2 and the speed change engaging device are controlled to be disengaged, respectively. The automatic transmission 20 is a stepped automatic transmission such as a planetary gear type or a constantly meshing parallel two-axis type, and the gear stages are switched by controlling the engagement / disengagement of a plurality of transmission engagement devices. When all the transmission engaging devices of the automatic transmission 20 are released, the power transmission becomes neutral, the second clutch C2 can be omitted, and the automatic transmission 20 can be used as the second connection / disconnection device. ..

The e-Axle unit 18 includes a second rotating machine MG2, and the second rotating machine MG2 is used as a driving force source for traveling to rotationally drive the left and right rear wheels 16. The second rotary machine MG2 is a motor generator that can be selectively used as an electric motor and a generator, is connected to the high voltage battery 86 via the PCU88 and the DC-DC converter 84, and is output from the HV-ECU 70. By controlling the PCU88 according to the MG2 control command signal Smg2, the PCU88 can function as an electric motor or a generator and the torque is controlled. The e-Axle unit 18 distributes the driving force output from the second rotary machine MG2 to the left and right drive shafts 32 by a differential device (not shown), and rotationally drives the left and right rear wheels 16. The e-Axle unit 18 corresponds to an electric drive unit that drives the other of the front and rear wheels.

The HV-ECU 70 includes a so-called microcomputer equipped with a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU processes signals according to a program stored in the ROM in advance while using the temporary storage function of the RAM. Is performed to execute various controls of the drive device 10. For example, output control of the engine 22 and the rotary machines MG1 and MG2, shift control of the automatic transmission 20, engagement release control of the clutches C1 and C2 (connection disconnection control), etc. are performed, and for engine control as necessary. It is configured separately for shift control, etc. The output control of the engine 22, the rotary machines MG1 and MG2 is basically performed according to the required driving force such as the accelerator opening θacc. Further, in the shift control of the automatic transmission 20, for example, the target gear stage is obtained according to a shift map defined with the required driving force such as the accelerator opening θacc and the vehicle speed V as parameters, or the driver's manual shift operation. The hydraulic control command signal Sat is output so as to be the target gear stage, and the gear stage of the automatic transmission 20 is switched.

The HV-ECU 70 functionally includes a traveling mode switching control unit 72 and an engine start / stop control unit 74. The driving mode switching control unit 72 switches a plurality of driving modes automatically according to a driving state such as a required driving force or a vehicle speed V, or according to a mode switching operation of the driver, and at least the engine 22 is required as a driving mode. A plurality of driving modes with different denials are defined. For example, in an engine running mode in which the engine 22 is used as a driving force source for running, the engine 22 is stopped and the first rotating machine MG1 and / or the second rotating machine MG2 is used as a driving force source for running. EV driving mode, series HV driving mode, engine driving in which the first rotating machine MG1 is rotationally driven by the engine 22 and the first rotating machine MG1 is regenerated and controlled, and the second rotating machine MG2 is operated by the obtained electricity. In the charging driving mode in which the first rotary machine MG1 is regenerated and controlled in the mode and the high voltage battery 86 is charged by the obtained electricity, the four-wheel traveling that outputs the driving force by both the 1M-HV unit 14 and the e-Axle unit 18. A mode, such as a two-wheel traveling mode in which driving force is output by only one of the 1M-HV unit 14 and the e-Axle unit 18 is possible.

The engine start / stop control unit 74 starts or stops the engine 22 in accordance with the start request and the stop request of the engine 22, for example, the engine 22 is started by switching the travel mode by the travel mode switching control unit 72. To stop or to stop. When the engine 22 is started and stopped, resonance occurs due to rotational fluctuations caused by a damper device or the like. Therefore, in this embodiment, the engine 22 is started and stopped while resonance suppression control is performed by the first rotating machine MG1. That is, when starting the engine 22, for example, signal processing is executed according to steps S1 to S9 in the flowchart of FIG. 2 (hereinafter, the steps are omitted and simply referred to as S1 to S9; the same applies to other flowcharts), and the engine is started. When stopping 22, for example, signal processing is executed according to R1 to R9 in the flowchart of FIG. The flowcharts of FIGS. 2 and 4 both include driving mode switching control by the traveling mode switching control unit 72, and S1 to S5 of FIG. 2 and R1 to R4 of FIG. 4 are substantially engine start / stop control units 74. Corresponds to.

FIG. 2 is executed while the vehicle is running in the EV running mode. FIG. 3 is an example of a time chart for explaining the change in torque of each part and the change in the operating state of the clutches C1 and C2 when the start control of the engine 22 is performed according to the flowchart of FIG. 2, and the time t1 of this time chart is shown. As previously shown, the torque (MG1 torque) Tmg1 of the first rotary machine MG1 and the torque (MG2 torque) Tmg2 of the second rotary machine MG2 are both in a positive output state, and the torque (engine torque) Te of the engine 22. Is 0. Further, the first clutch C1 is in the disconnected state, and the second clutch C2 is in the connected state. That is, the EV traveling mode at this time is an EV four-wheel drive state in which the driving force is output by the rotating machines MG1 and MG2 of both the 1M-HV unit 14 and the e-Axle unit 18.

Then, in S1 of FIG. 2, it is determined whether or not it is an engine start request for starting the engine 22. Specifically, the driving mode switching control unit 72 determines whether or not the mode switching determination for switching from the EV driving mode to the engine driving mode has been made, and if the mode switching determination for the engine driving mode is not made, the current S9 is present. When the mode switching determination for switching to the engine driving mode is made by continuing the EV driving mode of S2 or less, the engine start control of S2 or less is executed. The time t1 in FIG. 3 is the time when the mode switching determination for switching from the EV traveling mode to the engine traveling mode is made by the traveling mode switching control unit 72 and the determination in S1 becomes YES (affirmative). The engine start control of S2 to S5 may also be performed when switching to another driving mode that requires the engine 22, such as a series HV driving mode or a charging driving mode.

In S2, the MG1 torque Tmg1 of the 1M-HV unit 14 is gradually reduced so that the e-Axle unit 18 bears the entire required driving force, and the MG1 torque does not change so that the total driving force (= required driving force) does not change. The MG2 torque Tmg2 is gradually increased corresponding to the gradual decrease of Tmg1. The time t2 in FIG. 3 is the time when the replacement of the division from the 1M-HV unit 14 to the e-Axle unit 18 is completed and the e-Axle unit 18 bears the total driving force. When the replacement is completed, S3 is executed and the second clutch C2 is released to disconnect the first rotary machine MG1 from the automatic transmission 20. The time t3 in FIG. 3 is the time when the second clutch C2 is released and the first rotary machine MG1 is disconnected from the automatic transmission 20.

Subsequently, S4 is executed, and the first rotary machine MG1 and the engine 22 are connected by engaging the first clutch C1. The time t4 in FIG. 3 is the time when the first clutch C1 is completely engaged and the first rotary machine MG1 and the engine 22 are connected. In this state, S5 is executed, and the engine 22 is started while the first rotating machine MG1 performs resonance suppression control. The resonance suppression control controls the increase / decrease of the MG1 torque Tmg1 so that the resonance at the time of starting the engine is canceled, for example. The engine 22 may be started by, for example, starting control such as fuel injection and ignition while rotationally driving (cranking) the engine 22 by the first rotary machine MG1, or fuel can be directly injected into the cylinder of the engine 22. In the case of a direct injection engine, the cranking of the engine 22 by the first rotary machine MG1 can be minimized, fuel can be injected and the engine can be ignited and started. The period of time t4 to t5 in FIG. 3 is the start control time of the engine 22, and the fluctuation of the MG1 torque Tmg1 represents the resonance suppression control.

In the next S6, the rotations of the first rotary machine MG1 and the automatic transmission 20 are synchronized. Specifically, the MG1 torque Tmg1 and the engine so that the MG1 rotation speed Nmg1, which is the rotation speed of the first rotary machine MG1, matches the input rotation speed Nin of the automatic transmission 20 determined according to the vehicle speed V and the gear stage. Control the torque Te. The time t6 in FIG. 3 is a time at which the MG1 rotation speed Nmg1 substantially coincides with the input rotation speed Nin, and the MG1 torque Tmg1 and the engine torque Te are controlled to torques that are synchronous rotation speeds, respectively. The engine torque Te may be an idle torque, and the MG1 torque Tmg1 may be controlled to be a synchronous rotation speed. Then, when the MG1 rotation speed Nmg1 (= engine rotation speed Ne) substantially matches the input rotation speed Nin, S7 is executed, and the first rotation speed MG1 and the automatic transmission 20 are connected by engaging the second clutch C2. do. The time t7 in FIG. 3 is the time when the second clutch C2 is completely engaged and the first rotary machine MG1 is connected to the input shaft of the automatic transmission 20.

After that, S8 is executed, the MG2 torque Tmg2 is gradually reduced to make the driving force sharing of the e-Axle unit 18 0, and the MG1 torque Tmg1 and the engine torque Te are gradually increased by a predetermined driving force distribution to reduce the total required driving force. Is borne by the 1M-HV unit 14. As a result, the engine running mode is set in which the total driving force is output by the MG1 torque Tmg1 and the engine torque Te. The time t8 is the time when the replacement of the driving force from the e-Axle unit 18 to the 1M-HV unit 14 is completed and the engine running mode is switched to.

Next, the control when the engine 22 is stopped will be described according to the flowchart of FIG. FIG. 4 is executed while the vehicle is running in the engine running mode. FIG. 5 is an example of a time chart for explaining the change in torque of each part and the change in the operating state of the clutches C1 and C2 when the stop control of the engine 22 is performed according to the flowchart of FIG. As previously shown, both MG1 torque Tmg1 and engine torque Te are in a positive output state and MG2 torque Tmg2 is zero. Further, both the first clutch C1 and the second clutch C2 are in a connected state. That is, in the engine running mode at this time, the driving force is output by both the engine 22 and the first rotary machine MG1 in the front wheel drive state in which the entire required driving force is borne by the 1M-HV unit 14.

Then, in R1 of FIG. 4, it is determined whether or not it is an engine stop request for stopping the engine 22. Specifically, the driving mode switching control unit 72 determines whether or not the mode switching determination for switching from the engine driving mode to the EV driving mode has been made, and if the mode switching determination for the EV driving mode is not made, the current R9 is used. When the mode switching determination for switching to the EV driving mode is made, the engine stop control of R2 or less is executed. The time t1 in FIG. 5 is the time when the travel mode switching control unit 72 makes a mode switching determination for switching from the engine travel mode to the EV travel mode, and the determination of R1 becomes YES. The engine stop control of R2 to R4 may also be performed when switching from another running mode in which the engine 22 is operating, such as the series HV running mode or the charging running mode, to the EV running mode.

In R2, the MG1 torque Tmg1 and the engine torque Te of the 1M-HV unit 14 are gradually reduced so that the e-Axle unit 18 bears the entire required driving force, and the total driving force (= required driving force) does not change. MG2 torque Tmg2 is gradually increased as described above. The time t2 in FIG. 5 is the time when the replacement of the driving force from the 1M-HV unit 14 to the e-Axle unit 18 is completed and the e-Axle unit 18 bears the total driving force. At this time, the engine 22 is held at an idle torque capable of self-rotation, and the engine 22 and the first rotary machine MG1 are rotated and rotated at a rotation speed determined according to the vehicle speed V and the gear stage of the automatic transmission 20. There is.

When the replacement of the driving force is completed, R3 is executed and the second clutch C2 is released to disconnect the first rotary machine MG1 from the automatic transmission 20. The time t3 in FIG. 5 is the time when the second clutch C2 is released and the first rotary machine MG1 is disconnected from the automatic transmission 20. At this time, the engine 22 and the first rotary machine MG1 are held at, for example, the idle rotation speed of the engine 22. In this state, R4 is executed, fuel injection, ignition, and the like are stopped while resonance suppression control is performed by the first rotary machine MG1, and the engine 22 is stopped. In the resonance suppression control, for example, the MG1 torque Tmg1 is increased or decreased so as to cancel the resonance when the engine is stopped. The period of time t3 to t4 in FIG. 5 is the stop control time of the engine 22, and the fluctuation of the MG1 torque Tmg1 represents the resonance suppression control.

In the next R5, the engine 22 is disconnected from the first rotary machine MG1 by releasing the first clutch C1. The time t5 in FIG. 5 is the time when the first clutch C1 is released and the engine 22 is disconnected from the first rotary machine MG1. After that, R6 is executed to synchronize the rotations of the first rotary machine MG1 and the automatic transmission 20. Specifically, the MG1 torque Tmg1 is controlled so that the MG1 rotation speed Nmg1, which is the rotation speed of the first rotary machine MG1, matches the input rotation speed Nin of the automatic transmission 20 determined according to the vehicle speed V and the gear stage. do. The time t6 in FIG. 5 is a time at which the MG1 rotation speed Nmg1 substantially coincides with the input rotation speed Nin, and the MG1 torque Tmg1 is controlled to a torque that becomes a synchronous rotation speed. Then, when the MG1 rotation speed Nmg1 substantially matches the input rotation speed Nin, R7 is executed, and the first rotation speed MG1 and the automatic transmission 20 are connected by engaging the second clutch C2. The time t7 in FIG. 5 is the time when the second clutch C2 is completely engaged and the first rotary machine MG1 is connected to the input shaft of the automatic transmission 20.

After that, R8 is executed to gradually reduce the MG2 torque Tmg2, and the MG1 torque Tmg1 is gradually increased so that the total driving force (= required driving force) does not change to obtain a predetermined driving force distribution, whereby the 1M-HV unit 14 The EV four-wheel drive state is set so that the driving force is output by both the e-Axle unit 18 and the e-Axle unit 18. As a result, the EV driving mode is set. The time t8 in FIG. 5 is the time when the replacement of the driving force from the e-Axle unit 18 to the 1M-HV unit 14 is completed and both are assigned a predetermined driving force.

As described above, in the drive device 10 of the present embodiment, when the engine 22 is started or stopped while the vehicle is running, the entire required driving force is output by the e-Axle unit 18 and the second clutch is set. Since the engine 22 is started and stopped while the first rotating machine MG1 separated from the automatic transmission 20 by C2 controls the resonance, the first rotating machine MG1 is used to suppress the resonance without impairing the controllability of the driving force. Control can be performed appropriately. In this way, the engine 22 can be started and stopped while performing resonance suppression control at an arbitrary timing without impairing the controllability of the driving force while the vehicle is running, so that the usage time of the engine 22 can be reduced. Fuel economy can be further improved.

Although the embodiments of the present invention have been described in detail with reference to the drawings, this is merely an embodiment, and the present invention shall be carried out in a mode in which various modifications and improvements are made based on the knowledge of those skilled in the art. Can be done.

10: Hybrid vehicle drive 12: Front wheels (one of the front and rear wheels) 14: 1 M-HV unit (hybrid drive unit) 16: Rear wheels (the other of the front and rear wheels) 18: e-Axle unit (electric drive unit) 20: Automatic transmission 22: Engine 70: HV-ECU (hybrid control device) MG1: 1st rotating machine MG2: 2nd rotating machine C1: 1st clutch (disconnecting device)

Claims (1)

The engine includes an automatic transmission, a first rotating machine provided on the upstream side of the automatic transmission, and an engine detachably connected to the upstream side of the first rotating machine via a disconnecting device. And a hybrid drive unit in which the first rotary machine is used as a driving force source for traveling to drive one of the front and rear wheels via the automatic transmission.
An electric drive unit including a second rotating machine, which is used as a driving force source for traveling to drive the other of the front and rear wheels.
It is a drive device of a hybrid vehicle having
When the engine is started or stopped while the vehicle is running, the entire required driving force is output by the electric drive unit, power transmission via the automatic transmission is cut off, and the connection device connects with the engine. A drive device for a hybrid vehicle, which comprises a hybrid control device for starting or stopping the engine while performing resonance suppression control by the first rotary machine in a state of being connected to the first rotary machine.

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